INSIDE MYCORRHIZAE // PERFECTING pH // COCO COIR AUSTRALIA July/August 2015INDOOR GARDENING water use it wiselyFREE +Smarter Ways to Grow2015maximumyield.com The best hydro system for you new lighting technologies los angeles July 25-26 boston October 24-25
CONTENTS 44 July/August 2015FEATURES 24 34 38 42oooo oooo tNhsoyossweSteojwmu, yshtotaoustt?’vuaFersiterdi.sneItgncoiodtfhueaetdl,l,sGtyeoorcuougbinvnbdeeyecahudrytpditcrodoleedpsioenccnriaiidbcseegeswarrcihedosiecmndhmienhsogyigndanrgetorrdpoyo.fwonirincg systems to help make that choice a little easier.24 When 2 Become 1: 44 Perfecting pH 50 What Mycorrhizae Innovative Lighting Can Do For You Combinations by Dr. Lynette Morgan by Garrett Cropsey by Eric Hopper DEPARTMENTS34 The Chemistry of Coco Coir 8 From the Editor 53 10 Facts On 10 Letters to the Editor 54 Growers Know by Andrew Schell 12 Ask the Experts 56 Talking Shop 14 Max Facts 60 Distributors38 Growing 101: Choosing 20 Product Spotlight 62 Don’t Miss a Hydroponic System by Grubbycup42 Water Conservation and Hydroponics by Matt LeBannister4 Maximum Yield | July/August 2015
6 Maximum Yield | July/August 2015
FROM THE EDITOR | LINDA JESSON Deciding what growing techniques and products to use in your indoor garden can be overwhelming, given how many available options there are—but we are here to help! From our Product Spotlight section to our features on different growing methods and technologies, we have the details you need to make informed decisions. Are you thinking about switching up your lighting system? Long-time grower and product tester Eric Hopper has some suggestions on combining different innovative lighting technologies to better meet the spectral needs of your plants. And be sure to check out Grubbycup’s feature outlining different hydroponic systems and which situations each is best used for. Establishing and maintaining optimal pH levels is another important aspect of a healthy indoor garden, and expert gardener Dr. Lynette Morgan explains how to keep your garden in the ideal range. We round things out with features on mycorrhizal supplements, water conservation tips and coco coir. Finally, be sure to check out our features on twoMessage cutting-edge companies making waves in the Australian hydro industry—Sydney-based Hydro from the Masta and A-Grade Hydroponics in Melbourne. Editor For even more grow tips, explore Maximum Yield TV, our exclusive collection of how-toLinda Jesson videos, at maximumyield.com/mytv, and attend Maximum Yield’s Los Angeles Grow Gear Show, July 25-26. With hundreds of leading international exhibitors showcasing the latest gear and garden trends, free educational seminars plus a Grow Demonstration Area where you can see the latest set- ups and be entered for a chance to take one home— you don’t want to miss out! Visit indoorgardenexpo.com LOS ANGELES to plan your vacation. JULY 25-26 Be sure to follow Maximum Yield on Facebook, Twitter and Instagram to find all of the latest on-the- scene Expo highlights, along with even more tips and GGREOAWR tricks to help you maximise your efforts in the garden this winter. Connect with UsCONTRIBUTORSEric Hopper’s past experiences Grubbycup has been an avid indoor Dr. Lynette Morgan holds awithin the indoor gardening industry gardener for more than 20 years. B. Hort. Tech. degree and a PhD ininclude being a hydroponic retail His articles were first published in hydroponic greenhouse productionstore manager and owner. Currently, the UK, and since then his gardening from Massey University, Newhe works as a writer, consultant and advice has been published in French, Zealand. Lynette is a partner withproduct tester for various indoor Spanish, Italian, Polish, Czech and Suntec International Hydroponichorticulture companies. His inquisitive German. He is also considered one Consultants and has authored severalnature keeps him busy seeking new of the world’s leading authorities on hydroponic technical books. Visittechnologies and methods that could crochet hydroponics. suntec.co.nz for more information.help maximise a garden’s performance. Matt LeBannister developed a Raquel Neofit is a freelance writerAndrew Schell has 15 years of green thumb as a child, having been for the horticulture, travel and lifestyletechnical gardening experience, from born into a family of experienced industries. She has a background inwarehouse operations in Los Angeles to gardeners. During his career, he has business and radio, and is an avidthe full-sun fields of Humboldt County. managed a hydroponic retail store believer that hydroponics is the way ofWith a biochemistry degree from and represented leading companies the future. Follow Raquel’s writing atHumboldt State University and extensive at the Indoor Gardening Expos. Matt My Food Story on Facebook.lab experience, Andrew lends his view has been writing articles for Maximumof plants and nutrients from a molecular Yield since 2007. His articles arelevel. He is the in-house gardening published around the world.expert for Humboldt Wholesale.Garrett Cropsey is a biologist Become a Maximum Yield contributor and have your articles read by 250,000 readerscurrently living in Boulder, throughout the US, Canada, UK, Europe, New Zealand and Australia. Maximum YieldColorado. His love of nature began is the largest free-to-consumer indoor gardening magazine in the world. Every issue isin Longmeadow, Massachusetts, available on maximumyield.com, which has thousands of unique visitors monthly.where his first job was with thelocal parks department. He has adegree in ecology and evolutionarybiology from the University ofColorado Boulder.8 Maximum Yield | July/August 2015
LETTERS TO THE EDITORFelix Lewis Grower Gains Many Tips VOLUME 13 – NUMBER 2 July/August 2015 I enjoy reading Maximum Yield so much that my wife calls it my mistress! I spend much of my free time at home and at PRINTED IN AUSTRALIA work reading the magazine because it is so informative and Maximum Yield is published bi-monthly by educational when it comes to helping me improve my indoor and outdoor gardens. I look forward to reading every new Maximum Yield Publications Inc. issue. Thank you, Maximum Yield. I truly am a fan. 2339A Delinea Place, Nanaimo, BC V9T 5L9 Felix Lewis Phone: 250.729.2677; Fax: 250.729.2687 Grower Values the Basics No part of this magazine may be reproduced Maximum Yield provides useful, up-to-date information for without permission from the publisher. beginner and expert growers, covering all of our indoor needs. If undeliverable, please return to the address above. I was given a copy by my local hydro provider and immediately The views expressed by columnists are personal opinions and do not read it from cover to cover. There were lots of helpful hints on growing basics I otherwise wouldn’t have known about. necessarily reflect those of Maximum Yield or the editor. Anyone who loves to grow indoors, or even outdoors, should Publication Agreement Number 40739092 explore Maximum Yield. It truly is a good read. Adam Chickey PRESIDENT/PUBLISHER - Jim Jesson GENERAL MANAGER - Don MooresAdam Chickey Editor’s Note: Felix and Adam have each won a $100 cash prize BUSINESS MANAGER - Linda Jesson to spend at their favourite indoor gardening shop for telling us why they are fans of Maximum Yield. You can win, too! EDITORIAL Simply visit maximumyield.com/contests to enter. [email protected] from Each Page A Topic of Interest Editor Linda Jesson Assistant EditorsI have been reading Maximum Yield for I would like to suggest a futureyears! I learn something on every single article on enzymes. A lot of people Julie McManuspage. Now, I read the articles to my are paying top dollar for this product, Jennifer McGarriglechildren. Thank you. while others are using pool and pondMelinda E. enzymes. Although they are more ADVERTISING SALES economical, I question whether they Sales ManagerFuture Entrepreneur Feels Hopeful are a good substitute. Manufacturers do not list the exact enzyme mix Ilona Hawser - [email protected] wanted to say thank you for all of the they use, so it becomes difficult togreat information you put in Maximum choose a product by reading the Account ExecutivesYield. I read the magazine from front to label. You just have to try them and Kelsey Hepples - [email protected]. As an entrepreneur who plans to see for yourself. Some formulationsopen a hydro store, I find the Talking Shop are geared toward a specific goal, or Katie Rey - [email protected] quite useful, as they give me set of goals, from what I’ve gathered. Jed Walker - [email protected]. Thank you for all of your hard work. If someone could clear up the Robyn Jesson - [email protected] S. differences between these enzyme products, and what their intended PRODUCTION & DESIGNGreat Product Info uses are, it would be appreciated. [email protected] Enzymes play a major role in plant Art DirectorMaximum Yield is always letting me know processes, and I think they are worthy Alice Joeabout the new products I may need, and of some discussion in your magazine. Graphic Designersshares detailed information about those Jennifer Evertsproducts. Great read. Pip, via email Dionne HurdBrian G. Jesslyn Dubyna ACCOUNTING We Want to Hear From You! Tracy Greeno - [email protected] Email: [email protected] Katie LaFrance - [email protected] Facebook: facebook.com/MaximumYield Twitter: twitter.com/max_yield AUSTRALIAN DISTRIBUTION Dome Garden Supply Holland Forge House & Garden Growlush Hydroponic Generations Plant Symbionts Way to Grow UK DISTRIBUTION Nutriculture UK Direct Garden Supplies Dutch Pro Easy Grow Ltd. Erith Horticulture CANADIAN DISTRIBUTION Brite-Lite Group Eddis Wholesale Greenstar Plant Products Inc. Growers Paradise Quality Wholesale USA DISTRIBUTION Aurora Innovations BWGS General Hydroponics Humboldt Wholesale Hydrofarm Hydro International National Garden Wholesale / Sunlight Supply Tradewinds Urban Agricultural10 Maximum Yield | July/August 2015
ASK THE EXPERTSQ Is it true that spraying your plants with pure seltzer water is a form of CO2 treatment? Juan MartinezA T he short answer is: not in useful amounts, but such as potassium bicarbonate or potassium you might want to occasionally spray or water sulfate, is often added to raise the pH. Using too your plants with it anyway. much can lead to pH problems unless pH levels The long answer is the amount of carbon are monitored and adjusted. However, occasional dioxide dissolved in a litre of seltzer water use can still be beneficial to your plants. is pretty small compared with other ways of Basic (alkaline) additives are often made introducing CO2 into a garden. Simply talking of useful things. Potassium bicarbonate is an to your plants in close proximity would be organically acceptable fungicide that doubles as a a better, and cheaper, source of CO2. Using potassium source. Potassium sulfate is also known as sulfate of potash, which is used in fertilisers enough seltzer water to as a source of both potassium and sulphur. make a noticeable Depending on the particular water source, other difference in CO2 nutrients might be included as well. Mineral levels would not only water generally has at least 250 ppm of mineral be cost-prohibitive, salts and sulphur compounds. but it would also likely So, while seltzer water is not generally raise the humidity high considered to be an acceptable source of CO2 enrichment, it can be beneficial if used enough to encourage occasionally as a foliar spray or watered in as mould growth. Another a tonic. problem with using too much seltzer water is that Peace, love and puka shells, plain, carbonated water has a pH of 4 or so; to Grubbycup make seltzer water, a base, Grubbycup has been an avid indoor gardener for more than 20 years. His articles were first published in the United Kingdom, and since then his gardening advice has been published in French, Spanish, Italian, Polish, Czechoslovakian and German. He is also considered one of the world’s leading authorities on crochet hydroponics.12 Maximum Yield | July/August 2015
Processing Machine Reduces Waste A new $1.2-million, high-pressure processing machine in Western Australia is aimed at reducing food waste, improving the return on investment for growers and opening up export markets to the region’s growers. HPP technology provides a method of cold pasteurising fresh produce, making it safe for export without losing any of its nutritional value, says Jennie Franceschi, marketing director with Advance Packing and Marketing Services. “Cold pasteurisation kills pathogens and food becomes safer and has an extended shelf life with this treatment.” Research and development within the industry has focused on becoming better and more efficient at producing food, with little regard for using the end product, Jennie adds. “This was a big investment, but it’s about future-proofing our industry,” she says. (Source: freshplaza.com) MAXFACTS GROWING TIPS, NEWS AND TRIVIA Cauliflower Popular Despite Price Recent spikes in the price of cauliflower, attributed to supply issues, are not expected to affect future demand, according to AUSVEG; instead, the latest research data forecasts an increase in purchases during winter. The Nielsen Homescan data, taken from 10,000 Australian households, shows the amount of households buying cauliflower jumped by 81% between March and July 2014, and by 95% for the same period in 2013. “We’ve seen an abnormally high spend per household for cauliflower over the last three or four months,” says Kurt Hermann, AUSVEG assistant manager of industry development. The Homescan data also shows that other nutritious winter staples are back on the menu, with the amount of households buying sweet potatoes, pumpkins and broccoli increasing. (Source: ausveg.com.au) Government Grants Drought Assistance The Australian Government is providing $333 million to support farmers, farm businesses and rural communities affected by drought. The new funding includes: $250 million to continue existing drought concessional loans; $35 million for local infrastructure and employment projects; $25.8 million to manage pest animals and weeds in drought-affected areas; and $20 million to extend and expand existing social and community support, including mental health support and counselling, for drought-affected farming families and communities. Since July 2014, a new national approach to drought programs has been in place. The new approach replaces the Exceptional Circumstances arrangements and focuses on encouraging farmers to prepare for and manage the effects of drought and other challenges. (Source: agriculture.gov.au)14 Maximum Yield | July/August 2015
MAX FACTS GROWING TIPS, NEWS AND TRIVIA Aussie Veggies Popular in Asia Asian supermarkets will become vital to the Australian horticulture industry, predicts Bryan Balmer, the director of trade and investment at the Department of Economic Development. “Of the top 10 importers of Victorian horticultural products, only two of them are not part of Asia and that is the US and New Zealand,” Bryan told a Horticulture Centre of Excellence master class recently. “The quality of our products and our safety measures are a real point of difference to some Asian countries, and we’re also geographically close, which helps as well.” (Source: weeklytimesnow.com.au) Kiwi Storage Improvements There may be a simple and organic solution to improving the quality of kiwifruit during long-term storage. A new study from Iran recommends heat and calcium treatments to extend storage life and improve quality in kiwifruit. “A combination of heat treatment followed by a calcium dip for controlling post-harvest pests and diseases has had satisfactory results in maintaining or improving the texture of several products,” found Shirin Shahkoomahally and Asghar Ramezanian from Shiraz University. The researchers published the study in the March 2015 issue of HortScience. (Source: foodprocessing.com.au) Winter Veggies Washed Out While much of New South Wales lingers in extended drought, vegetable growers are battling with a case of too much of a good thing after massive rainfalls during April. The two tales tell a story of extremes—as their western counterparts deal with a second or third consecutive winter without a crop, those who copped the coastal low-pressure system earlier in autumn are still dealing with too much water. Vegetable growers in the Sydney Basin are reeling from the rain. Their crops were crippled and as temperatures plummet in the shift to winter, many growers are unable to produce a crop. (Source: theland.com.au)16 Maximum Yield | July/August 2015
MAX FACTS GROWING TIPS, NEWS AND TRIVIA Supersized Tomatoes When Spanish explorers first brought domesticated tomatoes to Europe 500 years ago, the fruit was already gigantic compared with its olive-sized wild counterparts. Researchers trying to understand the genetic basis of this girth have uncovered a way to make the fruits even larger. The team discovered this secret by studying two mutant tomato strains that had many branches coming off the upper part of the stem and produced unusually fecund fruits. Fruit size and other plant traits depend on what happens in the uppermost part of the stem, a growing tip called the meristem. The scientists discovered a feedback loop involving two genes—one to stimulate stem cell production and the other to hold production in check. A shortage of the latter leads to plumped-up beefsteaks, the team reports in Nature Genetics. (Source: news.sciencemag.org) Organic Farming More Profitable? Organic farming can make more money than conventional agriculture, says a new study analysing the financial performance of 55 different crops. Drawing on international data, including research from Australia and New Zealand, scientists found that organic agriculture is significantly more profitable than conventional farming and has more room to expand globally. David Crowder and John Reganold of Washington State University analysed the financial performance of crops on five continents over 40 years. Applying cost premiums made organic agriculture up to 35% more profitable than conventional agriculture. (Source: businessinsider.com.au) Consumers Unable to Afford Fresh Food Shopper Melissa from Numurkah in northern Victoria sums up the sentiment of many Australians when it comes to buying Australian-grown food. “It’s price. Everything keeps rising, costs go up, but our wages don’t.” Many farmers also relate to rising costs, no wage increases and consumers who can’t afford what they produce. For many, it is a simple equation that means their businesses are no longer viable. ABC Rural travelled to the regional centre of Shepparton to investigate what happens to a town, largely built from and supported by the fruit orchards, when Australians stop buying Australian produce. The region has struggled over the past decade with canneries buying less fruit as cheap imports flooded the market. Other processors in nearby towns shut down factories entirely and moved production overseas. This forced many growers to leave the industry, or to reinvent themselves and how they farm to stay viable. (Source: abc.net.au)18 Maximum Yield | July/August 2015
Avocado EducationThe Australian avocado industry is attempting to educate consumers on the correcthandling and ripening techniques for the fruit. More than 60 growers recentlydiscussed issues facing the sector, including inclement weather and branding.Avocados Australia chief executive officer John Tyas says producers must make surethe fruit is consistent in quality and ripe. “There is material that’s been developedto try to educate consumers about how to select, how to store and how to handlethe product,” he says. “A lot of consumers still don’t understand how a fruit ripens.If you put a hard avocado in the fridge, it’ll never ripen. Squeezing the fruit to test ifit is ripe could ultimately damage the produce, so delivering ready-to-eat avocadosto consumers can be challenging because as the fruit ripens and softens, it issusceptible to bruising.”(Source: abc.net.au)Local Greengrocers Experiencing a RevivalThe local fruit and veg shop may be experiencing a revival with Aussie shoppersincreasingly turning to specialist vegetable retailers to buy their favourite vegetables,says new consumer research. The Project Harvest study, which tracks consumerattitudes to vegetable purchases over time, shows the number of Australians who buytheir beans and carrots at greengrocers has jumped by 37% and 25%, respectively,since June 2014. “We know consumers enjoy the convenience of the major retailers,but this latest data suggests that for some Australians, there are other factors thatare increasingly leading them to shop at specialist vegetable retailers,” says KurtHermann, AUSVEG assistant manager of industry development. “Many consumers saythey shop at their preferred retailer because of the people, or because of the overallatmosphere and shopping experience there, and it looks like they’re finding this at theirlocal greengrocer.”(Source: ausveg.com.au) Maximum Yield | July/August 2015 19
SPOTLIGHTING THIS MONTH’SHOTTEST PRODUCTSAsk for them at your local indoor gardening storeGavita Holland SR and Wide ReflectorsGavita Holland is pleased to introduce two new reflectors: the SR reflector, designedfor optimal uniformity and light levels in smaller rooms where there is hardly any overlapbetween fixtures; and the Wide reflector for larger rooms, where lower intensities and ultimateuniformity are required. Specifically for the SR reflector, Mammoth Tents designed, in co-operation with Gavita, two new high-end grow tents. HPS reflectors always have a rectangularlight spread, never square. Therefore, these new tents are rectangular-shaped, offering a uniformityof more than 85% with a single fixture. The Mammoth G1 for one fixture and the G2 for two fixtures are 2.4-m high and come withMammoth Elite finishing, the highest-quality available today. For more information on these two new reflectors, visit an authorisedreseller near you. GrowSmart LED Gorilla Grow Grow Lights Tent Shorty 5’x5’ The GrowSmart range of modular LED grow lights Gorilla Grow Tent is pleased hails a new era of spectrum to release the Gorilla Grow control in horticultural Tent Shorty 5’x5’. The lighting. GrowSmart LEDs evolution of the world’s produce light in the parts of tallest grow tent into a the spectrum that are most super-short version is the useful to plants and avoid result of growers wanting the wavelengths of light that Gorilla Grow Tent quality andare redundant for plant growth. Each unit houses red, blue, ultraviolet strength, but requiring smaller tents to accommodate basements andand infrared emitters, and full-spectrum white LEDs. These additional spaces with lower ceilings. The Gorilla Grow Tent Shorty 5’x5’ fitswavelengths are important to plants at different stages of life. The big perfectly into these spaces at just 5-ft. tall, with the ability to adjust indifference with GrowSmart is the easy-to-use controller that enables 9-in. increments up to 6 ft., 6 in. This compact version of the Gorillausers to program their desired colour mix to run for a 24-hour loop, Grow Tent showcases the same intelligent design, 1680D fabric,and then adapt the photoperiod as the plant moves from germination, massive all-steel frame and game-changing features that have becomethrough vegetation and into flowering. Check out an indoor gardening synonymous with GGT. Visit a local retailer for more details.centre near you for more information. Lumatek 400-V Ballast and Globe Kit Lumatek is setting new benchmarks in the hydroponic lighting industry. Its new 600-W, 400-V lamp and ballast combination brings the best of Dutch lighting technology to Australian growers, providing a minimum of 5% extra plant light energy than a standard 240-V Lumatek ballast. The innovative technology behind Lumatek lighting provides a substantial increase in crop growth by delivering a better colour spectrum and more usable spectral energy. Although the 600-W ballasts are backwards compatible, ensuring you can use them with your 240-V MH or HPS globes, the best performance is achieved using the 400-V lamp and ballast combination together. Lumatek uses soft- and random-start technologies to avoid overloading electrical circuits, and cleverly integrates soft dimmer switching to protect your lamps. These kits can be used with any existing reflector and plug into a normal wall connection. Visit an indoor gardening shop for more details.20 Maximum Yield | July/August 2015
Growlush Digital Thermo ControllerTake control of your growroom and giveyour plants the right temperature atthe right time with the Growlush GLV3-1000, a dual-function temperaturecontroller. This productfeatures a solid ABS housing;an LED digital screen; aninput power cord with a three-pinpower plug; an output power cord witha grounded female connector; a probe cord; two indicator lights; and three settings. A heatingor chilling element will be required to work with this controller to keep target temperatures inrange. Simply set your desired temperatures and the temperature in your room will stay within1°C of your desired setting. The GL V3-1000’s waterproof tip allows you to use the device tocontrol the temperature of your nutrient tanks as well. For added convenience and safety, abuilt-in fuse in the controller will stop output when the power load is too high. Visit your localindoor garden retail store for more information. Gorilla Grow Tent Equipment Board Gorilla Grow Tent Equipment Boards are designed to hold fans, ballasts, controls and other grow gear to keep things organized. They also add strength to a tent’s overall structure. These boards are among the largest ones out there. The all-steel, reinforced construction complements the sturdy frames of Gorilla Grow Tents. Gorilla Grow Tents and Gorilla Grow Tent Accessories were invented by growers for growers to improve indoor growing and maximise yields. Look for Gorilla Grow Tent products at your nearest indoor gardening shop.groCELL Zelts and groCELL PyramidsPremium, German-made groCELL grow tents are great for beginners and perfect for growers whodon’t have a greenhouse or growroom. They provide great light and moisture control, and areportable and easy to assemble.The groCELL Zelt and the groCELLPyramid are made of completelylightproof, waterproof, air-tightmaterial and have a silver Mylar-lined interior. Inside there is 600Dpolyester aluminium coating andVelcro fasteners. These tents arePVC-free and come with removablewaterproof floor trays, adjustableinlet/outlet vents for fans and military-grade zippers.More special features include a front-viewing window,sufficient ducting holes and detachable windowflaps. groCELL Zelts are available in five sizes: theGC60, 80, 100, 120 and 150, while groCELL Pyramids are available in three sizes: the GCP80,120 and 150. Visit your local grow store for more information. Maximum Yield | July/August 2015 21
PRODUCT SPOTLIGHTGrowlush Hydro Series T5Propagation LightsGrowlush Hydro Series T5 Propagation Lights keep young clones,seedlings and mother plants happy and productive while reducingelectricity usage and growroom temperatures. Designed by industry-leading reflector manufacturer Growlush with 95% reflective aluminium,these propagation lights provide even light distribution and increased lumen output.Growlush Hydro Series T5 Propagation Lights can be placed within centimetres of a plant to maximise light absorption and increasesuccess rates without the risk of burning plants. They can also be hung sideways as supplemental lighting for mature plants. Encasedin a powder-coated steel housing with side vents to allow for cool operation, these fixtures are backed by a three-year warranty.Available in four sizes: the Hydro 22, Hydro 24, Hydro 44 and Hydro 48. Each unit comes with 6,500-K T5 bulbs so you can begingrowing straight out of the box. Visit your local indoor garden retail store for more information. Jupiter II Growlush Heavy Light Mover Duty Timer Box The Jupiter II Light Mover is The Heavy Duty Timer designed with industrial-strength Box “1 in 2 out” from components for years of ongoing Growlush is an industrial- resilience and dependability, grade timer built to last and features a unique Grav-A- with superior components. Track drive system that delivers Grow lights require a large load trustworthy, constant traction of power to strike the lamp, andfor durability. Cleverly engineered to use gravity, the weight of using a regular plug timer alone to controlthe reflector and a select pivot point ensures the drive wheel your lights will simply burn them out inis constantly in contact with the track. The drive wheel is the on position. Contactors are required tomanufactured from zinc-plated steel and bonded with UV- and safely switch HID lights on, as they are designed to take the load requiredozone-proof PVC nitrule tire. The jockey wheel includes fully sealed to strike the lamp. The Heavy Duty Timer Box has a built-in timer and plugball bearings, while the motor and gearbox is Swiss-assembled and sockets for total control of your lights. Use it to safely take the high loaduses updated, variable time-delay electronics. The Jupiter II range required to strike several lamps at once. It is CE-certified and can beis modular and designed to suit any size system. Light movers are used with multiple grow lights consecutively. Safety switches, individualproven to effectively enable a lower lamp height and provide light at fuses and a multifunctional timer will have your growroom runninga greater range of angles, reducing shadow patterns and enhancing automatically while you sit back and watch your plants grow. Visit yourlamp coverage. Visit A-Grade Hydroponics for more details. local indoor garden retail store for more information.O2 Grow 2040O2 Grow products from the Oxygen Research Group raise oxygen saturation levels 50% higher than what air stones can achieve. O2 Growemitter technology works by electrically separating the water molecule into hydrogen and oxygen. The pure oxygen is then re-absorbed back into the water. After years of controlled university studies, researchers logged, on average, 20% yield increases in tomatoes, strawberries, peppers and ornamental flowers. Supplemental oxygen is important whether you’re growing hydroponically or in soil. Oxygen at the root level helps prevent root disease, enhances nutrient uptake and helps balance pH levels. Increased oxygen is also essential for activating organic teas and nutrients. O2 Grow emitters come in a range of sizes to accommodate the amount of water you have in your reservoir. The O2 Grow 2040 is ideal for oxygenating 40 gal. of water. For more information, visit a hydro store.22 Maximum Yield | July/August 2015
by Eric Hopperoooo ooooWhen 2 Become 1: Innovative Lighting Combinations Making decisions about your indoor garden can be difficult, especially when it comes to your lighting system. Fortunately, growers no longer have to settle for one type of system. Different lighting combinations are quickly changing the way we view horticultural lighting.24 Maximum Yield | July/August 2015
INNOVATIVE LIGHTING COMBINATIONSAs demand for more efficient and LEDs continue to improve and becomeeffective lighting fixtures rises, instrumental for indoor growers. Afterlighting manufacturers continue The first generation of horticultural all, the customisable spectral output isto develop the latest and greatest in LEDs fell short of meeting the rigorous one of the biggest reasons why LEDshorticultural lighting. Although demands of the indoor gardener and are so unique.many advancements have been were a disappointment to say the least. The increasing number of manufac-made with high intensity discharge Fortunately, LED enthusiasts did not turers is also playing a large role in(HID) lighting systems, such as stop developing innovative products the practicality of horticultural LEDs.the availability of more efficient and over the last few years, horticul- These systems exploded in popularitydigital ballasts and enhanced tural LEDs have evolved into practical in all realms of lighting applicationsspectrum bulbs, other types of horticultural lighting solutions. Most of because of their high energy efficiency.innovative lighting technologies the advancements in LED lighting can This means more manufacturers areare quickly taking centre stage in be attributed to our ever-expanding committed to producing high-qualitythe indoor gardening community. understanding of plant physiology and LEDs. The horticultural industry reapsBoth light-emitting diodes manufacturers producing higher-watt- the rewards of the research and devel-(LEDs) and induction lighting age diodes. The more we understand opment performed by these compa-systems are rising in popularity how plants use particular wavelengths nies. A few years ago, 3- or 5-W diodesamong growers looking for high of light and which individual wave- for horticultural LEDs were virtuallyefficiency. Aside from coming lengths are best used in combination unobtainable due to the high cost ofa long way individually, these with each other for achieving optimal production. As costs decreased ontechnologies are being used growth, the more LED grow lights these higher-wattage diodes, horticul-together and their combination is tural LED manufacturers were able toquickly changing the way we view over the integrate them into their fixtures. Thehorticultural lighting. higher-wattage diodes give new horti- last few years, cultural LEDs the ability to penetrateoooo horticultural LEDs into the plant canopy in a manner have evolved comparable to HID lighting fixtures— into practical horticultural an attribute non-existent in the lighting first generation. solutions.” Induction Lighting Many years ago, Nikola Tesla pat- ented wireless transfer of power to electrode-less lamps and the concept of induction lighting was invented. Although Tesla may not have intended for his invention to be one of the most effective lighting sources for indoor horticulture, this has become the case.26 Maximum Yield | July/August 2015
INNOVATIVE LIGHTING COMBINATIONSInduction lighting uses a magnetron systems will not lose photosyntheti- for upwards of 10 years. Even plantsthat excites gases and metals within a cally active radiation (PAR) values over with higher lighting requirements cansealed bulb, which in turn produces the course of a growing cycle. In fact, be grown using induction fluorescentslight. A sealed bulb means there are induction lighting technologies can for 5-7 years before there is ano protruding electrodes—the biggest hold their PAR value for multiple noticeable reduction in PAR.contributor to the degradation of most years, which can provide the growerartificial lighting sources. with consistent results cycle after cycle. Sulphur Plasma – Sulphur plasma Most horticultural bulbs need replace- Currently, there are two types of induc-ment annually, but induction lighting tion lighting systems used for indoor lamps use a small, fused quartz spherelasts longer and runs more consistently horticulture: induction fluorescents that contains sulphur and argon gas.than other systems. Induction lighting and sulphur plasma. Sulphur plasma lamps use radio fre- quencies to excite the sulphur and ar- Induction fluorescents – gon, causing them to illuminate. This Induction fluorescents differ is similar to the way the sun produces light, meaning sulphur plasma lighting from regular horticultural is able to produce a spectral output close to that of sunlight. The colourLongevity fluorescents in a few rendition index (CRI) and correlatedcombined ways. As previously colour temperature (CCT) of sulphur mentioned, plasma lighting are the closest to induction lighting sunlight of any artificial light source. requires no As with induction fluorescents, the unique induction design means the with superior spectral output are electrodes. PAR output will degrade slowly. Lon-what make sulphur plasmas one of Have you ever gevity combined with superior spectralthe most sought-after horticultural noticed the area output are what make sulphur plasmas one of the most sought-after horticul- closest to the tural lighting systems available. Like LEDs, as more companies start to pro-oooolighting systems available.” electrodes turns duce sulphur plasma lighting systems, dark brown or the technology will get even better and black as regular the price will eventually start to drop. fluorescents age? A sulphur plasma lighting system will This is because the quickly pay for itself through accrued electrodes protruding energy savings. into the bulb cause Combining Lighting Technologies the internal components The most innovative lighting systems to leak or burn off, which currently available are based on a com- bination of technologies. Lighting fix- means the bulb loses its tures that combine HID lighting along with LEDs have been available for some effectiveness. This depreciation time, and more recently, induction light manufacturers (both fluorescent in PAR is the reason fluorescent and sulphur plasma) have been using LEDs to make their lighting systems the bulbs must be replaced annually best in the business. The most commonly used LEDs in for horticultural purposes. these combined technology systems are the red-spectrum LEDs. Deep-red Because induction fluorescents LEDs (620-660 nm) are used in com- bination with induction fluorescents have no electrodes, they can and sulphur plasma lighting to provide retain a consistent light output28 Maximum Yield | July/August 2015
INNOVATIVE LIGHTING COMBINATIONSthe ideal spectrum for chlorophyll B’s It is this oooopeak absorption. This leads to morebountiful flower sites and larger flower particular spectrum role lighting sources like LEDs willsets. Considering both induction tech- produced at play in indoor horticulture. Cutting-nologies provide full-spectrum lighting edge horticultural lighting systemswith high CRI ratings, the addition of sunset that allows such as induction fluorescents and sul-red-spectrum LEDs is specifically aimed photosensitive plants phur plasma systems are exactly whatat creating larger and more prolific to enter a fruiting or the indoor horticulture communityblooms. Induction lighting systems flowering period even needs to continue moving forward.combined with high-wattage red-spec- when the dark period is Combining induction technologiestrum LEDs are, in my opinion, the ulti- far less than 12 hours with particular wavelengths producedmate horticultural light source when it by LEDs is a way to integrate the bestcomes to efficiency and effectiveness. in duration.” of both worlds: full-spectrum lighting with a focus on high-energy bloomingStaying in the Red The added spectrum produced by these spectrums. This combination will help LEDs simulates the spectrum produced meet the strenuous demands of theSome induction lighting manufactur- by the sun at sunset and triggers the indoor garden and will allow growersers have taken light manipulation of flowering response more quickly. The to better mimic the way plants respondphotosensitive plants to a whole new simulated sunset spectrum allows plants to natural light. As new technologieslevel with the use of other red-spectrum to relax more quickly when entering are developed and existing technolo-LEDs. Our evolving understanding of the dark cycle. gies are refined, a combination of in-plant physiology has recently discov- Plants grown under traditional light- novative technologies will likely be theered that particular wavelengths in ing cycles can take up to three hours to answer to providing gardeners with anthe red spectrum are responsible for relax into a state where they begin the optimised lighting system.triggering the flowering response in flowering response while plants pro-plants. In nature, this far-red spectrum vided with the 720-740 nm spectrum atis present right as the sun is setting. It the end of the light cycle will act moreis this particular spectrum produced at like plants grown outdoors. The big-sunset that allows photosensitive plants gest advantage of lighting systems thatto enter a fruiting or flowering period use the 720-740 nm LEDs is that theyeven when the dark period is far less allow the grower to increase the lights-than 12 hours in duration. This is why on duration by an hour or two. Thisoutdoor plants, even photosensitive provides more energy to the plants andones, will begin flowering long before helps them produce larger and morethe equinox. However, in a typical prolific flower sets.indoor garden, the light spectrumdoesn’t change as the lights turn off. T he more we learn about how par-Instead, it is an all-or-nothing situa- ticular wavelengths of light affecttion where the entire light spectrum the way plants grow, the larger theprovided to plants is instantly turned todarkness as the lights are switched offby the light timer. Many growers are not aware that theactual triggering of flowering occursduring the dark cycle, not while thelights are on. This is why traditionallighting cycles are based on a 12-hours-on and 12-hours-off photoperiod.Photosensitive plants grown indoorsrequire at least 12 hours of darknessto properly trigger their floweringresponse and to produce bountifulflowers. Innovative horticultural light-ing manufacturers, particularly thoseproducing induction technologies, arenow integrating 720-740 nm LEDs thatcome on at the end of the light cycle.30 Maximum Yield | July/August 2015
The Chemistry of Coco Coir by andrew schell Coco coir has become a popular and effective growing medium for indoor and outdoor gardeners. Our horticultural chemistry expert Andrew Schell has the details on what exactly coco coir is made of and how to best grow with it. For starters, using a coco-specific base nutrient is the key to successful gardening with this medium.34 Maximum Yield | July/August 2015
THE CHEMISTRY OF COCO COIR The coconut’s fibre has found its way into many products, including cars,packaging, insulation, ropes and matting, and many growers are now using coco coir as their gardening medium of choice.C oco coir is the value than a base nutrient ground-up seed ideal for soils and hydroponics. husk tissue from The microflora living in cocothe coconut palm tree requires nitrogen and removes it from(Cocos nucifera). It is an the coir in a process called nitrogen drawdown.environmentally friendly grow To balance this drawdown, a coco-specific base nutrientmedium since coconut husk is should have a higher nitrogen percentage than a base for soila renewable, biodegradable resource. and hydro.Almost 3 billion coconuts per year are Since coconut trees grow by the ocean, coco coir containsharvested in Sri Lanka alone. Other major producers a high concentration of sodium and chlorine that can beof coco coir include India, Mexico, the Philippines, Guyana, detrimental to plants in high concentrations. A good-qualityCosta Rica and Indonesia. The coconut’s fibre has found coco medium should be thoroughly washed and leachedits way into many products, including cars, packaging, of these elements. Also, coco treated in an alkaline (basic)insulation, ropes and matting, and many growers are now calcium nitrate solution saturates binding sites of the cocousing coco coir as their gardening medium of choice. fibres, preventing possible deficiencies. Pre-soaking the The layer of the coconut containing the tissue that becomes fibres in an alkali treatment increases the tensile strength ofcoco coir is called the mesocarp. While it looks and feels coco fibres by almost 30%. Check to see if the manufacturerlike soil, coco coir is an inert medium that also shares many of your preferred coco brand is buffered with calcium.properties with hydroponics. Primarily, coco coir holds a As a rule of thumb, be cautious when selecting bales andsubstantial amount of water, holding almost 10 times its own bricks of coco. The drying and compressing of the fibresweight in moisture. The tough-yet-lightweight fibres are also creates dust, and it is a lot of work to decompress coco coir.resilient to the elements. Most bales of dried coco are compressed in a 6:1 ratio. Too Coco’s woody, structural tissues consist of roughly two-thirds often, waste-grade coir and coir dust is pressed into thesecarbohydrates and one-third lignin. The carbohydrates are bricks. The medium needs to be sieved to remove the smallthe complex polysaccharides cellulose and hemicellulose. particulates. A high-quality coco should not contain any dustLignin is a complex polymer. These are the most prominent or tiny coco particles, as it can be compacted easily, therebyorganic polymers on Earth. With large reserves of cellulose depriving plant roots of oxygen and water.and lignin as energy storage, coco coir readily becomes a The pH of coco coir is naturally between 5 and 6.5—anbreeding ground for beneficial micro-organisms. ideal range for most plants. This gives the medium a distinct The beneficial microcosm in the root zone of plants advantage over other mediums that need pH conditioninggrown in coco can also include plant-growth-promoting before use. Coco works best with 10% recycled glass stones orrhizobacteria (PGPR) and many beneficial fungi, including perlite added to it to aerate it further and prevent compaction.mycorrhizae, yeasts and more. Fungi such as Aspergillus Earthworm castings can also be added to stimulate thenidulans produce enzymes called cellulases that break microbial community. Coco can be reused for a total of threedown the cellulose in the coco fibres. At this point, the full indoor runs. Between each run, additional glass stones orcoir becomes a carbon source (energy) for all the micro- perlite should be added. After harvest, you can add enzymesorganisms in the soil and the plants themselves. and flush solutions to pre-treat the medium and remove any Using a coco-specific base nutrient is the key to successful leftover salts and organic matter from the last run.gardening with this medium. Coir possesses significant With a little practice, coco growers can get the flavouramounts of natural potassium (K) and phosphorus (P). It and aroma of soil gardens along with the efficiency andalso contains trace amounts of nitrogen (N), calcium (Ca), productivity of hydroponics—the best of both worlds!magnesium (Mg), boron (B), chlorine (Cl), copper (Cu),iron (Fe), manganese (Mn), molybdenum (Mo) and zinc(Zn). A base nutrient designed for a coco grow mediumshould reflect this composition and should have a lower P-K36 Maximum Yield | July/August 2015
GROWING 101: by Grubbycup So, you’ve decided to give hydroponic gardening a try. Now what? First of all, you need to decide which hydroponic yoSuotn,hyesooyessduet’vetjeomusdsdyteetscocstiitdeduaemersdtewsit.nhotIgonicgohithvhuheeetylh,pdsGyremdorcrpuaoookbpnnebodicyntciahscuryagtsptiatcecrdldmheeeosnitncioicnreaigubsasaeees.tlrirGtciyte.rolseNumbdoebmewaysscoiiwugenpnhr.geadrtde?osFfwcoirririsnbtgeosfsaolml, e common growing systems to help make that choice a little easier.38 Maximum Yield | July/August 2015
There are many different hydro- often, it doesn’t have enough access While creating a watering schedule, aponic systems available to garden- to air, and the plant will drown. In my little too dry is a smaller error than aers, each meeting plant needs in experience, the most common error little too wet. Here are some commonslightly different ways. While the in gardening is overwatering. On the growing systems.choices can seem intimidating at other hand, just as with people, toofirst, they have much in common. much air and too little water causes Containers and Soilless MixesRoots, and the plants they are dehydration, but of the two scenarios,attached to, require above all slight dehydration is a less traumatic The benefits of growing plants in potselse access to both air and water. experience than a slight drowning. of soil are numerous. Soil buffersNutrients are also important, but against changes, provides structurethat’s a topic for another article.For now, let’s assume the nutrientscan be added to the water to makea nutrient solution. Most of the differences betweengrowing systems are in the specif-ics of how they make water and airavailable to the root system. Forexample, a houseplant in a flowerpot filled with soil may get wateredfrom a watering can, and is allowedto dry out somewhat betweenwaterings, giving the plant accessto both water and air. If the plantisn’t watered, it will dry out anddie, but if the plant is watered too“IN MY EXPERIENCE, the most common error in gardening is overwatering.” Maximum Yield | July/August 2015 39
HYDROPONIC SYSTEMSand support for roots, and is a familiar for the average houseplant. There are Active Hydroponicsmedium to many. The drawbacks? a variety of soil alternatives available,Soil-based gardening tends to be each with slightly different watering Hand watering works well as long as theheavy—large pots are required—and needs, since some hold water longer gardener has the time and patience tosoil holds moisture so well that it is easy than others. do it regularly. The addition of a pumpto overwater plants. Soilless mixes are to the system creates an active hydro-designed to mitigate these drawbacks Passive Hydroponics ponic system and can save effort.by using ingredients such as peat, coir Sprinkler systems use pumpedand compost. These mixes tend to If a plant pot is filled with a grow water to spray the top of thebe lighter and are commonly used in medium, and set in a tray with water, media, which soaks down to thenurseries for potted plants. They can it is a passive hydroponic system. As root system. Aeration is achievedbe hand-watered to provide moisture, the media dries, capillary action draws by using fresh water and allowingand allowed to dry slightly between water to the roots either directly from the media to partially dry beforewaterings to provide access to air. the tray or through a wick, although watering. Sprinkler systems areThis is considered a hydroponic in practical applications, occasion- often run to waste, meaning runoffmethod of growing since plants ally watering the top of the media to is not recovered, or as part of aare not grown in soil, but introduce new solution can help flush recirculating system. They arethe experience is similar to the media. The media should be airy inexpensive, but generally less exactgrowing in soil, which makes or allowed to dry slightly so water is not than other systems. The spray cansoilless mixes a good choice allowed to stand long enough for the be difficult to contain, and dissolved oxygen to disperse and start therefore traditional sprinkler systems are to become anaerobic. This type not recommended of system is simple to set up, and for a home indoor can be an easy first step into the garden where water world of hydroponics. Simply damage may result. fill a pot with your chosen grow Drip media, such as perlite, set in a tall dish or 1020 tray, and Drip systems use water by hand with a hydro- pumped water and low-volume emit- ponic nutrient solution as ters. The slow-dripping needed. For the price of action allows the water to some grow media and a be absorbed over a longer period of couple of bottles of fertiliser time, allowing for greater penetration you can try a simple passive hydroponic system. “SOIL BUFFERS against changes, provides structure and support for roots, and is a familiar medium to many.”40 Maximum Yield | July/August 2015
with less runoff and uncontrolled drain) systems flood the medium When considering which system is bestspray than traditional sprinklers. containing the roots and then allow for a given situation, take a look at allAeration is regulated by the media the water to drain away, giving the the available options. Many commercialused, the amount the media is roots access to air. A timer usually kits are available, often using a combi-allowed to dry between nutrient controls the waterings. A well- nation of the above principles. Whenapplications and the amount of air aerated solution will help buffer considering which is most appropriatebubbled into the solution. minor overwatering. for your needs, look at how each supply water and air to the root system. Soil isNutrient Film Technique Deep Water Culture common, but tends to have the most insect issues. Hand watering worksNutrient film technique uses a Deep water culture systems can be well for a few plants, but can becomelow volume of nutrient solution as simple as letting the roots dangle arduous if there are a large numbercontinuously applied to the roots. in a nutrient solution and adding of plants to be tended. Pre-fabricatedAn NFT system functions much an air stone for aeration. Because systems are more expensive, but DIYlike a continual drip. The roots are air is pumped into the water, the systems tend to require more creativ-constantly exposed to a thin film solution does not go stagnant and the ity and a good understanding of theof aerated nutrient either with or plant can absorb both air and water. principles involved. Aeroponic systemswithout a mat used as a grow medium. These simple systems are sometimes make beautiful roots, but requireAeration needs are met by the referred to as bubblers. continuous electrical usage with littleexposed roots above the film or mat, tolerance for a power failure.and by use of an aerated solution. Aeroponics Now that you know the basics of Ebb and Flow Aeroponic systems use the same basic growing and have an idea about which principles as DWC, but instead of system or systems you might want Ebb and flow adding air to the solution, the nutrient to try, visit your local hydroponics (also called retailer to learn more. flood and solution is sprayed into the air and onto the roots. Maximum Yield | July/August 2015 41
CWanodaHtneysrderrvoaptbyoMaittoLenBannniistecr shydroponic gardeners understand the importance ofconserving water—a hydroponic garden uses less water than a traditional, soil-based garden, and many growers decide to use this method of growing because of that simple fact. But there are ways to cut down on water usage even more.There are many advantages to hydroponic • Gardening in the basement rather than other gardening over traditional, land-based farm- parts of your home can help keep your reser- ing, including that drastically less water is voir and grow space cooler. needed. It is one of the main reasons many • Venting your room frequently with a power- of us choose to garden hydroponically ful inline fan can help maintain the cooler and why many nations with limited water temperature your plants thrive on. Using air- cooled reflectors are an even more direct way resources and harsh climates are turn- of removing the large amount of heat pro- ing to hydroponics as their preferred duced by HID grow bulbs. Or you can grow method of farming. Even with these with LED lamps, which run cooler than HID lighting systems. advantages, there are many ways we can increase water savings with our • Reservoir chillers are another way to keep hydroponic systems and further your reservoir cool and prevent evaporation. Reservoir chillers are submersible refrigera- lower our carbon footprints. tion units that keep your nutrient solution at a temperature ideal for plant growth. Eliminate Excess Heat Preventing evaporation will conserve water and prevent the nutrient solution from Heat is one of the biggest becoming too concentrated. enemies of water conserva- tion when gardening with • Keeping your reservoir covered will also help prevent evaporation and keep algae growth hydroponics. Too much heat down, eliminating the need to empty and in the growroom will cause change your reservoir due to the buildup of algae and reservoir sludge. Some reservoirs water to evaporate and come with lids or you can use black and white plants to drink more than plastic over top to reflect light away while they would in cooler preventing evaporation. rooms. There are sev- eral ways to effectively eliminate heat in the growroom:42 Maximum Yield | July/August 2015
“THE GENERAL RULE OF THUMB FOR DUMPING THE WATER AND REPLACING THE NUTRIENT SOLUTION IN YOUR RESERVOIR IS EVERY 5 - 7 DAYS.”Reservoir Water Changes Another reason people empty their The few residual nutrients will only reservoirs sooner than the typical 5-7 benefit your plants and you can saveAnother way water gets wasted in the days is that there is a buildup of oxygen- litres and litres of water each week.growroom is too-frequent reservoir robbing and pump- and tube-clogging Water conservation is an issue thatwater changes. The general rule of algae and reservoir scum and it needs affects us all. As global populationsthumb for dumping the water and to be cleaned out. This buildup can be continue to rise and urbanreplacing the nutrient solution in your prevented by keeping light from enter- environments become increasinglyreservoir is every 5-7 days. Nutrients ing your reservoir, circulating the water crowded, the issue of how to ensureare consumed by the plants and need with a pump, using multiple air stones the world’s water supplies are notreplacing within that time frame. to oxygenate your solution and adding depleted will continue to draw There are numerous reasons reservoirs hydrogen peroxide periodically. attention. We can all do our part,get changed sooner than necessary. especially hydroponic gardeners,One reason is simply the over-eagerness Water Conservation if we follow a few simpleof novice gardeners who are afraid of techniques that will help usnutrient deficiencies/toxicities and are Now that you have eliminated the use as little water as possiblenot equipped with an EC pen. Nutrient reasons why you might have to replace in a responsible way.levels in your reservoir drop gradually your nutrient solution more frequentlyas they are consumed by your plants. than normal, there are easy ways toIf left too long, plants can develop conserve water when you do have todeficiencies, causing growth to become empty your reservoir. Instead of simplystunted. The opposite can happen as pumping the old reservoir solutionnutrient levels build up when your grow down the drain, why not use it to waterspace is too warm and water evaporates your lawn, your outdoor vegetable andfrom your reservoir. Having an EC, TDS flower gardens, or your houseplants?or ppm pen to measure your nutrientlevels is essential. This way if levels aretoo low they can be topped up for ashort period of time. If levels are toohigh, extra water can be added to lowerthe nutrient concentration and preventnutrient toxicities. Maximum Yield | July/August 2015 43
PerfectingpH-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 by Dr. Lynette Morgan Keeping pH within the correct range means your plants will have access to the full menu of essential nutrient ions for optimal growth and productivity. Few things in life are perfect, but a grower needs to do whatever it takes to get their garden’s pH levels as perfect as possible. 44 Maximum Yield | July/August 2015
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PERFECTING pHThe pH of the nutrient solution is a major factor in will typically show up as iron deficiency on new foliagedetermining the uptake rate of many essential nutri- (yellow, interveinal chlorosis on the foliage) and as tipent ions. Run pH too high and the dreaded nutrient burn and leaf cupping, which are symptoms of a reduc-lockout looms. Often, the first sign pH has drifted out tion in calcium availability and uptake. Inexperiencedof range is a slight paling or yellowing of the younger growers may misinterpret these nutrient deficiencyfoliage as the plants struggle to take up certain symptoms as a problem with the nutrient formulation oressential nutrients. Many inexperienced growers tend product itself, rather than an issue with pH rising aboveto misinterpret this, so a quick check of pH is always optimal levels for iron and calcium uptake.worthwhile when troubleshooting growth problems. “A quick check of pH is always worthwhileWhat is pH? when troubleshooting growth problems.”In simplest terms, pH is a measure of the acidity or What Causes pH Fluctuations?alkalinity of a solution. The pH scale is logarithmic,which means a pH of 4 is 10 times more acidic than In a healthy, well-run hydroponic system, pH fluctuations area pH of 5 and 100 times more acidic than a pH of 6. normal and in some instances, such as a recirculating nutri-With a pH of 7 being neutral, such as with pure water, ent film technique system with a large crop of mature plantsvalues below 7 are acidic and those above are alkaline and small nutrient volume, pH changes can be quite rapid(or basic). Plants grown in hydroponics have a dif- and require frequent adjustments to stay within a narrowferent optimal pH level than those grown in soil. For range for optimal nutrient uptake.most commonly grown hydroponic crops, an optimal As plants remove nutrient ions from the solution, thepH range is between 5.5 and 6.5. solution’s pH drifts up or down. If left uncontrolled, the Maintaining the optimal pH range is important pH will often drift downwards for several days after plantingbecause it affects the solubility, availability and a new crop, after which the pH will steadily increase. Thisuptake of several of the essential plant nutrients.If the pH drifts too high (past 7), plant uptake pHis due to the differential uptake of ions from the solution,Morganof some nutrients becomes less efficient. For with the release of hydrogen (H+) or hydroxyl (OH-) ions from the root system. As positive ions such as cations Ca2+,example, plants can become iron deficient, K+, Mg2+ are removed from the solution, hydrogeneven if sufficient iron is present in the nutrient ions (H+) are released from the root system tosolution. equalise the ratio of anions to cations in the root zone and this lowers the pH ofperfectingCalcium is also affected by high pH, the solution. When the crop begins an5forming insoluble salts that active growth phase, anions such as NO3 are taken up, which increasesprecipitate out of the nutrient the pH through the release ofsolution to form whitish hydroxyl ions (OH-) into solution.deposits, called scale, Once plants are well-established,on reservoir walls, most hydroponic systems tendchannels and equip- to see a gradual and continualment. This type of increase in pH over time, whichnutrient lockout is countered with doses of diluted acid.The ideal pH rangefor most hydroponicplants is 5.5-6.5,with many havinga narrower optimallevel of 5.8-6.-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 46 Maximum Yield | July/August 2015
Water Supply and Treatment “Once plants are well-established, most hydroponic systems tend to seeMany pH problems originate from the water a gradual and continual increase insupply. Many source waters, including city water, pH over time, which is countered withcan have issues with alkalinity and while that isnot a problem for human consumption, it can doses of diluted acid.”cause problems in a hydroponic system. A watersupply with a high starting pH and a high alkalin- Large plants in a recirculating systemity takes a far greater volume of acid to bring it with a small reservoir will see moredown to optimal levels than a water supply with rapid pH changes thana low alkalinity and of the same pH. Alkalinity is plants in a system withusually provided on water analysis reports from a larger volume ofthe city and is worth checking if continual pH nutrient solution.rises requiring large doses of acid is a problem. High alkalinity is greater than 300 mg/L ofcalcium carbonate and low alkalinity is less than100 mg/L. When high-alkaline water is first addedto the nutrient reservoir, it can take large volumesof acid (pH-down solution) added over a numberof days to finally bring down and stabilise the pHin the 5.8-6 range. However, adding large amountsof acid is not only time consuming, but it can alsocreate imbalances in the nutrient ratio as acidsalso add in nutrient ions. Nitric, phosphoric andsulphuric acid all add N, P or S to the nutrientsolution, so accumulations can occur. Growers withan alkaline water supply can prevent this issue bypre-acidifying the source water down to a pH of6 before using it to make up nutrient solutionsor adding as top-up water to a nutrient reservoir.Once the water supply is stabilised at a pH of 6 andthe alkalinity countered to the point, it remainsat that pH for 24 hours and can be used in thehydroponic system, and less acid will be requiredfor pH control.Nutrient Formulation and pHNutrient formulations or products all havedifferent starting pH values because individualsalts become more or less acidic when dissolvedinto water. Salts such as monopotassium phosphatelower the pH more than salts such as calciumnitrate. Most formulations will result in an initialpH of around 5.5-6, which is ideal for the growth ofhydroponic crops.-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Maximum Yield | July/August 2015 47
PERFECTING pH-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14In hydroponic solutions, some salts can be used to influ-ence the pH control of the nutrient solution, reducing therequirement for acids during the growth phase of the crop.Ammonium nitrate is one salt used for this purpose, andthe optimal amount provides 10-15% of the total nitrogenof the formula in the ammonium form. Ammonium innutrient solutions tends to be acidifying because, unlikenitrate, it is a positive ion, and when taken up by plants itis replaced by hydrogen ions, reducing pH in the rootCF = 60 | pH = 8 zone. In addi- tion, ammonium forms ammonium hydroxide and hydrogen ions produce a mild acidifying effect. Many of the nutrient products on the market designed for hard or alkaline water sources use a certain percentage of ammonium nitrateCF = 60 | pH = 7 to help counter pH increases. While this is effective in keeping pH Nutrient solution formulation and water supply alkalinity also levels down, the ammo- play a role in pH changes in the root zone. nium form of nitrogen Testing and Adjusting can cause growth issues The pH of a nutrient solution can be easily adjusted with the use of specifically designed pH up and down and even toxicity if the products that are diluted and ready to use. Commercial growers usually make up their own pH adjustment percentage used is too solutions of 10% nitric or phosphoric acid or potassium hydroxide for increasing pH. By using a ratio of 50% high or under certain nitric and 50% phosphoric acid, the solution can be kept growing conditions. “The ammonium form of nitrogen can cause growth issues and even toxicity if Ammonium competes the percentage used is too high.” for calcium uptake, so only small levels— 10-15% of total nitro-CF = 60 | pH = 5.5 gen—of ammonium as a nitrogen source are recommended for most crops and well- formulated nutrient products usually contain less than this. The effect of increasing pH on the solubility of the nutrient solution.48 Maximum Yield | July/August 2015
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 in better balance as both N and P are added, but Testing equipment when a lot of acid is used, the nutrient solution doesn’t have to should be adjusted for these additional N and be expensive. P sources, as they are macronutrients. There Test strips, kits are organic acids such as citric acid and white and pH pen vinegar that are sometimes used in small systems meters are to bring pH down, but these are weak acids readily available. and only provide a short-term pH reduction. Organic acids also add carbon to the nutrient Different solution, which microbes (both good and bad) Hydroponic love to feed on, encouraging an unwanted Systems reduction in dissolved oxygen in the solution. With recirculating “With large, rapidly growing systems, checking pH is simple, plants, there will usually be slight as the solution in the reservoir is what is in directdifferences in pH between the feed contact with the roots. For media-based systems,nutrient and the leachate solution.” which are often drip irrigated and in which the nutrient solution may not be recirculated, pH control A wide range of pH testing equipment is is slightly more complex. For these types of systems, available, from inexpensive liquid test kits and pH needs to be measured both at the nutrient supply strips sold by aquarium suppliers to high-tech, reservoir and in the solution that drains from the base electronic meters. Test kits and strips should only of the grow beds, bags or slabs containing the plants, be used for the lower pH range—many of these called the leachate solution. measure pH 5-7. Growers with electronic meters With large, rapidly growing plants, there will usually should also invest in a cheap liquid pH test kit be slight differences in pH between the feed nutrient or strips just to double-check the accuracy of and the leachate solution—pH changes as the their electronic meter from time to time. Meter solution flows past the roots and has ions absorbed probes tend to drift over time and need to be or released, and the grow medium may influence calibrated on a weekly basis, cleaned and replaced pH as well. Adjustment of pH at the nutrient supply annually. Meter calibration is essential and often reservoir should be based on the pH measured in the overlooked by many growers—electronic pH leachate draining from the plant’s root system. For meters usually come with buffers. A pH 4 and a example, if the pH is 6.9 in the leachate and 6.2 in pH 7 solution can be used to check and adjust the the feed solution, the pH of the feed solution should meter’s readout. Additionally, buffer solutions are be acidified down to the point where the drainage usually available through hydroponics retailers solution starts to come down to between 5.8 and 6, as and are a good investment. Always follow the this is the pH the root system will be experiencing. instructions for your pH meter. Some require the probe to be stored wet, others don’t. Cleaning the Measuring and adjusting pH in a nutrient solution is sensitive probe tip is also important for accuracy. usually quick and easy. There is a wide range of pH testing tools and adjustment products on the market to choose from and retailers can provide valuable advice on what is most suitable for different types of systems. Keeping a garden’s pH within the correct range means your plants will have access to the full menu of essential nutrient ions for optimal growth and productivity. Maximum Yield | July/August 2015 49
by Garrett CropseyWHAT MYCORRHIZAEYouCAN DO FORMycorrhizae is the symbiotic relationship betweenfungi and plant roots. To understand the benefits ofadding mycorrhizal fungi to your garden, it’s importantto understand the basic nature of the relationshipthese fungi form with different substrates and plants.50 Maximum Yield | July/August 2015
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