March 18, 2011

The Tantalizing Prospects of Hydroponics

I am fascinated by technology, both in my field of horticulture and in most other venues of the modern world. I remember going to Disney World about 25 years ago and seeing "the future of gardening" at Epcot. The future looked pretty bright, with mechanized automated planting of vegetable and grain crops growing in hydroponic media, or in no media at all. The sight of mature lettuce plants sliding around on an elevated rail system with their root systems totally exposed to the air was a sight to remember, tagged with the term "aeroponics". Long before there was a Green movement, hydroponics had the potential to save huge amounts of water, produce huge amounts of  food or foliage, and save huge amounts of fertilizer runoff.

tomato seedling
 Hydroponics has enormous potential for growing plants in controlled environments to produce high yields of product, without the conventional in-the-ground techniques of sunshine and soil. Some of the greatest promises of hydroponics are that the methods can be employed in hostile environments, indoors, underground, or even in space. Israel, Japan ( until recently) and the UAE are leaders in closed-environment hydroponic systems, and produce staggering amounts of food per acre. There is a gentle resurgence in combining hydroponic growing with aquariums, using the water from the aquarium to fertilize the plants, and letting the plant roots filter the aquarium water. There have been substantial experiments done in this hybrid style of system, and the results were impressive. Fish farming and hydroponic horticulture go together perfectly and everyone seems to win. The success would beg the question: why hasn't hydroponics caught on a lot more, and why don't we see huge hybrid aquaculture / hydroponic farms all over the country ?

a simple hydroponic plant watering system

The primary answer is simple, yet depressing: large agricultural hydroponic systems cost big money up front, and venture capital is hard to come by for a "farm". Secondarily, I believe there is  resistance to the idea of growing food plants hydroponically, for many more subtle reasons. It may be because of the complicated-looking equipment needed, or the maintenance of the pumps and tanks. It may possibly be due to the idea that hydroponic fertilizers cost more, are constructed differently than "mainline" brands, and are often harder to find at your local garden store than the types we are all used to using. I have heard people talk about losing the connection to Mother Earth by using the "sterile" methods of hydroponics and that the food tastes different. Let me see if I can de-mystify some of these ideas.

Suncurve experimental hybrid aquaculture-
hydroponic system

Eurofresh Hydroponic Farms- Arizona

Hydroponics is the science of growing plants without soil or in water. Many people have grown an ivy or spider plant in a bottle of water on the kitchen windowsill for years; hydroponics at its simplest.  Loosely stated, plants can be grown in anything that supports their root systems, and allows roots to respire. Many inorganic soil-less media are quite successful  in other venues of horticulture, namely in the orchid business. Fired clay pellets, glass beads, and rockwool are all common media in the orchid world, many of which were borne of the hydroponic world. European growers have used hydroponic methods for decades in growing a great many plants in very small areas under dismal weather conditions. Orchid plants can be grown to magnificent dimensions in the stable and stress-free world of artificial light and on-demand fertilizing.

Table-top hydroponic gardens have been showing up in retail catalogs for the last few years, showing a group of vegetables large enough for a Texas ranch growing in a table-top garden 2 feet long. ( This is misleading advertising). The idea is sound, though, that a unit with a self-contained, recirculating water environment with a predictable light source can grow plants in otherwise difficult situations. Taken to a larger scale, desert states and countries have been using such closed-loop systems for 30 years or more, and all that's necessary for inputs is electricity for the lights and pumps. The numbers are impressive; it is easily possible to produce 3 to 10 times as much per acre with hydroponics than by conventional farm methods. It is easy to produce hydroponic organic vegetables and food products, given the exclusion of pests and diseases from the environment. Without the need for routine pesticides, organic gardening comes easily.

There are, of course, downsides to hydroponics. One must keep the system clean and running smoothly, and take extra care not to contaminate the plants or fertilizers with outside pathogens or pests. One would need to do routine pH and fertilizer tests to make sure the plants adequately tended, and that light bulbs are replaced on schedule. This is routine hygiene for many venues of gardening, just in a different mode. If we can get past the fear of the technology and the up front costs even for small units, I think people will find that hydroponics can make gardening a lot easier and more productive than they'd ever thought possible. After all, how else could you grow a tomato in a condo in Minneapolis in the winter, or have a vertical garden in an apartment in Manhattan ??

Vertical Garden- courtesy of Arch Planners

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