Top : Float systems allow for easy inspection of root health . Below : A wide range of greens can be grown in small float systems .
FLOAT VS . DFT SYSTEMS
Float , raft , and pond systems are methods of solution culture where plants are supported by a sheet of lightweight material , typically polystyrene , that floats on the surface of a large pond of nutrient solution . Seedlings are usually raised in a separate nursery area , sown into either blocks of inert propagation media like stone wool or into small tubes or lattice pots of substrate . Once the seedlings have reached an optimal size , they are inserted into holes cut into the floating rafts and set adrift on the nutrient pond . Roots develop down into the nutrient solution , which supplies mineral elements and dissolved oxygen for root respiration . The top of the plant develops , supported only by the raft ( a fact that does limit the types of crops growers can choose to cultivate ). The rafts of plants are easily moved over the surface of the nutrient pond with a gentle push as the floats act as a frictionless conveyor . In larger ponds or raceways , floats of new seedlings are introduced at one end of the nutrient pool and gradually move towards the opposite end as the plants mature . At the furthest end , floats are lifted for plant removal at harvest before being cleaned and replanted with new seedlings . Larger plants like tomatoes , cucumbers , and melons use similar set-ups in which the crops are stationary and supported by overhead wires . Often , these are DFT systems , meaning the nutrient solution flows past the roots . The continual flow of solution in DFT systems prevents stagnation and delivers fresh supplies of dissolved oxygen to the root system .
Maximum Yield 69