The following information is based on material found in my book, BIG DOLLARS GROWING GOURMET SALAD GREENS. To find out how to get your own copy, CLICK HERE.

ORGANIC AND REGULAR:

It's a misnomer when we speak of organic hydroponic systems. Most organic gardeners need soil before they'll appreciate the term organic. Hydroponic systems do not use soil. (This doesn't mean you can't have a greenhouse with soil beds inside. That's what most growers had in the past.)

However you can use organic fertilizer in a hydroponic system. But your choice of media is restricted. NFT and aeroponics will not do because they will not be able to house micro-organisms which are needed for the breakdown of certain organic compounds. Your best selection of media would be pea gravel, lava rock or perlite which can be top fed or flooded like the ebb and flow system.

Organic mixes can be readily made at home. Don't use fish emulsion - it's too smelly. Fish flour is better. Check your supplier for the various organic solutions available.

THE PRODUCTION OF LETTUCE IN A HYDROPONIC SYSTEM:

Though growing lettuce hydroponically is a demanding job, that isn't the real problem. Selling the crop for a profit is the real problem. As in any business the only short cut to success is knowledge of your product, its market and a desire to pay attention to detail. Once you get past the two-person or family operation, labor, high energy costs and high-cost structures will eat up your time and profit.

If you settle your goals on a smaller finely tuned market like gourmet salad greens, coupled with an efficient housing and growing situation, you won't have much interference from large competitors. The large grower cannot profitably handle small individualized markets.

Lettuce can be grown in gravel beds or on horticultural rockwool slabs (about 30 inches by 12 inches by 3 inches). Flood benches or what is known as "Flood and Ebb" are also used. The methods I advise you to use are regular NFT, the one called NFT Trough and possibly the A-frame which the Irish use with such good results.

FLOOD BENCHES:

Or Flood and Ebb: a flood bench is one with a plastic top on which you can set potted plants. The entire bench top is like a large pan into which you can flood nutrient and/or water to a certain level. For lettuce crops you fill the bed with a mixture of pea gravel and river sand, place the lettuce cubes at proper intervals into the mix (about six inches apart on the diagonal as in the intensive gardening method). Now let the nutrient flood into the mix and rise to the surface level. Hold it there for a few minutes, then let it drain back out again.

The time spent holding the liquid at that level depends upon the crop and the air temperature. After the plants have picked up some ample moisture, the fluid is returned to a storage tank from which you can pump again at regular intervals (as determined by your crop growth). Most growers who use this method believe it saves time and labor as well as water and fertilizer. The Japanese like it very much - almost as much as they like to grow with lights. The big problem with this method is the expense in setting it up.

Thinking of installing this system? First consider the following. Get a really tough plastic top to fit into the bench-bed. It must be so tough that when you lay the gravel/sand mix in it you won't puncture holes in it. Have benches which can be leveled in every direction. Always know the EC (electrical conductivity) and the pH of your medium and nutrient/water system. Keep all test instruments clean and test at least once a week. Remember, the benches must be sturdy - water and gravel are heavy materials.

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