The Lettuce Raft system
As the name implies, this system is ideal for growing lettuce and leafy greens. Particularly since these plants love moisture and have a minimal root system. Additionally, lettuce has a short growing cycle and a relatively low height. It doesn’t need staking to support the plants. The Lettuce Raft system allows you to grow your plants hydroponically, in water without soil, and at a minimum cost.
The rafts in this system are boards, usually made of polystyrene (styrofoam), that float on top of nutrient-rich water. Although 1″ thick boards will work, it is far safer to use 1 1/2″ to 2″ thick boards. Use the compressed boards, not the beaded ones, or you will have a mess everywhere when you cut them to size.
<2>Nutrient Container
The nutrient container can be any type of waterproof, watertight material. Tote boxes are cheap and easy to use, just try to get them with straight sides. If the sides slope in, the raft will hang up and the lettuce roots will not touch the water; or the space around the raft will allow light to enter the nutrient solution allowing algae to develop.
Plant Containers
Small pots with openings on the sides hold the transplanted seedlings and fit into holes cut into the foam. Net cups are the easiest, but solo cups can be drilled out to allow the roots to escape and water to enter.
Note: If you cannot find a tote with fairly straight sides, or you do not feel confident in cutting the styrofoam options are available. Make the “raft” large enough to sit on the top of the tote or container. Since this raft needn’t float, the lid of the container will work well. You then have a choice of either a straight Kratky system or a Deep Water Culture system. Instructions for these are found elsewhere on this site.