Total Control Gardening with Home Hydroponics

Here's a straightforward, comprehensive guide to home hydroponics without the usual hype.


| October/November 1998



home hydroponics - illustration of hydroponics setup

The basic components of a home hydroponics system.


BETH GLICK

Please don't skip this article on the assumption that it's just one more wildly inflated puff job promising GIGANTIC YIELDS FROM ONE SQUARE FOOT or TOMATOES THE SIZE OF MELONS from some AMAZING NEW INDOOR GARDENING SYSTEM.  Here is the plain truth about modern hydroponics systems.

It's a sad fact that we home gardeners (who spend billions every year on North America's number one productive pastime) are exposed to more harmless quackery, hype, and exaggerated promises than any consumer group but dieters and black-bass fishermen. And no area of gardening has been subject to more shameless huckstering than hydroponics: the art and science of growing plants in a sterile flowing nutrient bath under high intensity sunlamps.

But every year, a fresh crop of tabloid ads appears for the latest indoor "magic garden" — a flimsy plastic planter hiding some kind of worthless patent-pending plumbing gimmick. You fill it with "magic soil," add "magic seed," dose it with "magic food," set it in a sunny window or under a feeble little fluorescent "magic light," and wait for "magic crops" that never happen. In truth, there is no magic to modern home hydroponics. And none needed. The equipment and skills employed are much the same as you've likely used in setting up and managing a plant-filled tropical-fish aquarium: a straightforward mix of elementary plant science, practical and easily understood electric water-pump and lighting technology, all leavened with the gardener's gentle art. Hydroponics works beautifully with nearly any flower or food plant ... and can yield flowers and produce in a fraction of the area and in about one-third less time than in the very best outdoor gardening year. Honest!

Over the last two decades, the development of reliable techniques and instructional materials for amateurs, as well as innovative homescale adaptation of professional greenhouse equipment, has made hydroponics readily available to home gardeners at a cost that may be high initially, but that will be repaid with year-round fresh vegetables of matchless quality and small fruit that would cost you $2.50 a pound in any store.

Picking Your Rooting Medium

In nature, a young plant sinks roots deep and spreads them wide into the surrounding sod to support stem and leaves and to access water, oxygen, and food. The tough fibrous main stem and branch roots anchor the plant against weather and browsing animals. To get water along with the mineral nutrients dissolved in it, the plant sends out millions of fragile microscopic feeder-root hairs—minuscule tubes of thin, semipermeable membrane through which water molecules can pass. In nutrient-short soil, or where competing roots from neighboring plants abound, or where the above-ground structure is trodden or pulled frequently by feeding livestock, the plant will devote energy to growing a stronger root system rather than to producing the edible leaves, stems, or fruits that you want for supper.

In hydroponics, none of these natural stresses occur. A plant will grow just enough root to keep its stem immobile and will generate the minimum of feeder roots needed to absorb food — the nitrogen (N), potassium (K), and phosphorous (P) that are familiar to gardeners — as well as a dozen or two other minerals. In hydroponics, the plant doesn't have to extract nutrients from surrounding soil minerals; a balanced diet is provided in ready-to-absorb form in its nutrient bath. But every agitation of the stem will encourage unneeded root production; the plant's base must be firmly supported from the day the seed sprouts.

Peat moss, sawdust, wood chips, chipped bark, sand, gravel and crushed rock, gardener's heat-expanded mineral soil conditioners (such as perlite and vermiculite mixed with sand), expanded clay pellets, and other chemically stable media are used as hydroponic rooting media with varying degrees of success. Coarse sand is most popular where it's most abundant, in desert areas, and works adequately. Sawdust (most commonly used in logging country) and peat do not drain well and can waterlog and rot. Both are naturally acidic. Some gravels contain limestone that will bias pH; they can contain soil, decayed vegetation, and plant pathogens as well. The manufactured soil conditioners are sterile, pretty much pH-neutral, and all-natural; perlite consists of little white popcorn-like puffs made by heat-expanding a volcanic rock that is high in silica; vermiculite is made much the same way from mica. Very lightweight, they will blow around when dry and can waterlog. They also break down relatively quickly.





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