Hydroponics: Successful Surfing

Hydroponics was once thought simply to be the growing of plants without soil. It has since evolved into a science--the growing of plants in a nutrient solution with or without an inert medium such as gravel, sand, peat, vermiculite, perlite, rockwool, coir or sawdust--and one that requires specific knowledge, capital and perhaps a bit of fearlessness.

Another derivative of evolving modernity is the Internet, which some would say also requires a bit of savvy and fearlessness. However, nowhere is there such an amassed amount "f information so readily available as on the World Wide Web. Following are listings of Web sites that GPN found useful for the beginner or the established hydroponic vegetable grower, as well as for those on the fence.

Why or why not hydroponics?

It is always a good idea to know all the benefits gained from beginning or switching to a different technique. The pros of hydroponics are endless and include fewer soil-borne pests and diseases, no weeds, less labor-intensiveness, greater plant allowance within a smaller space, more quickly grown plants with higher yield, water and fertilizer conservation and more control over nutrient levels and fertilizer absorption (www.archimedes.galilei.com/raiar/histhydr.html).

Yet, with advantages come disadvantages. In a more basic, just-the-facts-ma'am type of site simply entitled "Hydroponics" (www.oswego.edu/nova/facts/hydroponics/hydroponics.html), some of the disadvantages along with the advantages are outlined as well as pros and cons of various kinds of media and hydroponic system types. The site notes that without question, one of the biggest drawbacks of hydroponics is the cost, both for the initial capital investment and for the advanced heating, cooling and irrigation systems required.

General overviews

If you are a beginning grower, or even if you're not, it is sometimes advantageous to begin with the basics. The Greenfingers site (www.greenfingers.com.au/services/digging_deeper/growing_hydroponic_veg.htm) by Malcolm Campbell is a good place to start. He gives a general overview of hydroponics and discusses the pluses and minuses of using hydroponics, the use of different types of media, various locales for your hydroponic crop and sowing techniques.

The Foothill Hydroponics Library site is also a good site for beginners, or for those who need a reminder of why they initially chose hydroponics. The site offers a very helpful brochure called The 5 Ws of Hydroponics (www.foothillhydroponics.com/brochure/

5ws.htm). Questions addressed include: Why hydroponics? When do I use hydroponics? Where can hydroponics be used for maximum benefit? How can I actually use hydroponics? What is a growing media? and Which types of systems may be used for hydroponic irrigation? Also found on the site are other links to articles and brochures with diagrams and recommendations for the beginner.

Commercial hydroponics

Beginning a hydroponics business, or adding hydroponics to your existing operation, is never an easy task. Like all start-ups, the odds are stacked squarely against you. You should consider your market, skill level (both in growing and in management), growing environment, financial standing and the amount of sweat equity required. A good summary of things to consider can be found on the Practical Hydroponics & Greenhouses Web site at www.hydroponics.com.au/back_issues/issue06.html and www.hydroponics.com.au/ back_issues/issue07.html.

Hydroponic techniques

In addition to knowing the basics, it is important to be aware of the different hydroponic techniques and discern which one adequately meets the needs of your particular situation. While the general overiews are good sites from which to glean basic information, they are limited in terms of intermediate to advanced hydroponic growers' needs. Aquamist, a hydroponic products store, describes the various kinds of hydroponic techniques on its site (www.aquamist.com/hydroponics), and while the information is still somewhat basic, it provides a good stepping stone to choosing the right technique for your operation.

A discussion of hydroponic techniques would be remiss without also discussing a somewhat recent technology called aeroponics in which, according to the International Society for Soiless Culture, "roots are continuously or discontinuously in an environment saturated with fine drops (a mist or aerosol) of nutrient solution" (www.hydroponics.com.au/back_issues/issue05.html). This technique, though proven highly successful, is often not used by commercial vegetable growers since it is initially costly and perhaps overly mechanical and delicate for some growers.

Growing hydroponic vegetables

Though growers can grow almost anything hydroponically, there are certain vegetables that perform exceptionally well in pricing studies. Those top performers are typically high-quality salad crops-- tomatoes, cucumbers, lettuce, spinach--that have been shown to provide break-even or better revenues in hydroponic systems (www.ag.arizona.edu/hydroponictomatoes/overview.htm).

Tomatoes are the highest of the top performers, according to the University of Arizona. They are one of the most commonly grown hydroponic vegetables since 4.3 billion tomatoes are consumed in the United States alone. Due to the relatively high cost of hydroponic growing, tomatoes are among the most likely crop to recoup the extra expenditure in capital, automation and energy costs required for hydroponics. When consumers are willing to pay 2-3 times more for a better tomato, hydroponic tomato growing can be highly lucrative. On its site, Growing Tomatoes Hydroponically (www.ag.arizona.edu/hydroponictomatoes/overview.htm), the University of Arizona recommends greenhouse and environmental control system types, offers propagation techniques, illustrates proper growing media for plant types, plant nutrition, pest and disease control and provides harvest information for hydroponic tomatoes.

North Carolina State University (NCSU) and Mississippi State University also offer wonderful sites (www.ces.ncsu.edu/depts/hort/greenhouse_veg/topics/topics-pages/GH_Tomato_Production.html and www.msucares.com/pubs/pub1828.htm, respectively) devoted to hydroponic tomato production, though you will need Adobe Acrobat to view the presentations. NCSU lists statistics, common grower problems, types of tomato crops that can be grown, costs and possible returns on investment, and recommends the best growing media, structures, production systems, growing times, insect population monitoring systems and insect biocontrols. MSU offers variety information, pruning advice, temperature, humidity and pH recommendations, a planting schedule and lists nutrition deficiency symptoms.

While tomatoes are the most common hydroponically grown greenhouse crop, growers also grow lettuce, spinach, cucumbers and other veggies. For a listing of several Web sites for commonly grown hydroponic vegetables, including tomatoes, cucumbers and lettuce, visit the University of Florida's research and education site at www.nfrec-sv.ifas.ufl.edu/gh_&_hydroponics.htm#GH%20Crops. Though directed primarily at Florida growers, the information is still pertinent to most growers? needs. The University of Florida also illustrates effective cucumber and tomato growth using perlite media (www.nfrec-sv.ifas.ufl.edu/keys_to_success.htm) and has several links devoted to seed sources, greenhouse design, nutrient solution formulation and their own vegetable production handbooks (www.nfrec-sv.ifas.ufl.edu/gh_&_hydroponics.htm).

Cornell University, like the University of Arizona, North Carolina State University and the University of Florida, has its own controlled environment agriculture program. The program grows hydroponic lettuce, spinach and pak choi. Their lettuce, spinach and pak choi handbook sites are located at www.bee.cornell.edu/extension/CEA/LettuceHandbook/Lettuce%20Intro.htm; www.bee.cornell.edu/extension/CEA/Spinach_Hanbook/index.html; and www.bee.cornell.edu/extension/CEA/Pakchoi_Handbook/index.html, respectively. The sites offer greenhouse hardware and environmental control system recommendations and advice on production, transplanting, crop health, harvest and postharvest procedures. Also available are images of various growth stages for each vegetable.

Proper electrical conductivity and pH levels for hydroponic vegetables

The GTG Hydroponics site (www.gtghydroponics.com/veggiph.htm) is an excellent resource for determining the proper pH level of the particular hydroponic vegetable you are growing. Once you have determined the proper pH for your particular crop, consult Practical Hydroponics and Greenhouses' article "Calibrating pH & Conductivity Test Pens" (www.hydroponics.com.au/back_issues/issue09.html) to learn how to properly measure the pH and electrical conductivity of your crop.

Also discussing the proper way to measure for pH and EC is the University of Massachusetts' site (www.umass.edu/umext/programs/agro/floriculture/floral_facts/phecpens.html). The site describes how to calibrate and use the "pen" correctly to measure pH and EC, and lists additional supplies needed. In addition to the proper use of the pen, the site explains how to extract growth medium samples and interpret the test data. The site is based upon bedding plant data, but the directives are the same for hydroponically grown vegetables, with the exception of pH levels, which should be predetermined for the particular vegetable you are growing.

Nutrient management

Practical Hydroponics and Greenhouses is also an exceptional resource for nutrient solution management of hydroponic vegetables, and offers a 4-part article on issues concerning proper nutrient management. Part one introduces the principles involved in nutrient management, though it is not available on the Internet and must be requested directly. Similarly, part two discusses the general principles of nutrient management, including water quality, fertilizers and nutrition in open and closed conditions (www.hydroponics.com.au/back_issues/issue14.html). Part three concerns recirculating systems and discusses the two different kinds of closed recirculating systems as well as different management techniques, EC and pH control, water quality, the dumping of extraneous nutrient solution, bleeding and waste management (www.hydroponics.com/au/back_issues/issue16.html). Part four of the article, dealing with management of open or non-recirculating systems, is also unavailable on the Web site and must be requested directly.