Water-Culture Systems

These systems do not use any medium other than water, so they require a support material such as wire mesh to keep the plants from drowning. These systems rely on regular contact between plant roots and the nutrient solution. Leafy crops like lettuce and herbs tend to do better in water culture than do fruiting crops like tomatoes, cucumbers, or peppers.

Raft System (active or passive)
In this system, plants float on rafts above a reservoir of nutrient solution. (Styrofoam rafts work well in the classroom.) The tips of the roots reach the liquid and the holes cut in the raft for the plants allow some air exchange. Many raft systems also aerate the water automatically, to provide the roots with greater exposure to oxygen.

NFT (Nutrient Flow Technique) (active)
Plants are suspended in the nutrient mix, which is pump-circulated past the roots, aerating the solution. Commercial growers often place seedlings directly into rockwool cubes within holes cut in PVC pipe channels.

Aeroponics Systems (active)
At regular intervals, plants suspended in the air are sprayed or misted with the nutrient solution. This technique, dependent on high-tech growing methods, is the one used by Disney's Epcot Center.

The aeroponics unit pictured at right is available from the Gardening with Kids store.

 

 

 

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