Recent developments in hydroponic cultivation techniques have made hydroponic gardening accessible to commercial growers and home gardeners alike. Complete starter kits are available for most hydroponic techniques and do-it-yourself plans are available. Most systems can be hand or automated watered by a pump and timer.
Different plants respond better to different techniques depending on its water and support needs. Decide which plants you would like to grow, then choose the technique that best supports the type of plant you want to grow.
The Nutrient Film Technique, also known as NFT, uses a trough or tube as a growing bed. A thin film of nutrient solution is pumped to one end of the tube. The slightly angled tubes keep the water flowing downhill. Holes in the top of the tube allow the plant to dangle its roots into the water film. The nutrient film technique is best for small plants such as lettuce and herbs.
Raft, Float or Deep Culture
The deep-water culture technique is a simple noncirculating system. A piece of foam insulation floats on the nutrient solution tank. Plants are held in net pots suspended in holes in the foam. The roots dangle into the water. Some systems use an aquarium air pump and air stone to aerate the nutrient solution, other systems rely on the gap between the plant and the nutrient solution to provide oxygen to the plant. Deep culture technique works best for lettuce, basil, Swiss chard, cucumber, mint and similar leafy crops, but any crop can be grown with a sufficient air gap.
Plants in a container or frame dangle their roots into a root chamber and sprayed or misted with a nutrient solution. The mist keeps the roots moist, and excess solution condenses on the sides of the container and returns to the nutrient tank. The aeroponic technique requires the use of a pump and timer and is highly susceptible to power or equipment failure. Many crops can be grown using aeroponics especially for root crops such as potatoes, carrots and beets.
Ebb and Flow
The ebb-and-flow technique is one of the most popular hydroponic systems because of its ease of use and success with many different plants. A growing medium such as rockwool, clay pellets, gravel, sand or other inert substances supports the plant and retains moisture while allowing the roots to obtain oxygen. The ebb-and-flow technique is also called flood and drain because it works by alternately flooding the growing medium with nutrient solution and then allowing the solution to drain away. The nutrient solution drains back into a holding tank until the next flood cycle. The plants are flooded between one and four times a day depending on the type of plant and the moisture retaining properties of the growing medium.
Drip irrigation systems are also popular and appropriate for most plants. The plants are grown in a growing medium and the nutrient solution is dripped onto the surface of the medium. The nutrient solution percolates down through the growing medium and can be collected and recycled or allowed to drain away. One variation on the drip irrigation technique includes vertical towers of plants watered at the top with the nutrient solution trickling down to the plant below it. Another variation grows plants in bags or tubes of growing medium that either lie flat on the ground or are hung vertically. A drip emitter waters the plant and a hole at the end of the bag allows excess nutrient solution to drain away.