Hydroponics: Successful Surfing

August 20, 2002 - 11:51

Internet resources for the beginning, intermediate and advanced hydroponics grower.

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...
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.

About The Author

Elizabeth Pensgard is an editorial assistant for GPN.

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