Lettuce (Lactuca sativa) is probably the most efficient crops to grow hydroponically. It belongs to the Asteraceae daisy group. Known for being a leaf vegetable used in salads and other food items, it is also used for its stem and seeds. Hydroponic lettuce is quite popular as it grows quickly and does not require full sunlight and nutrient solutions for lettuce do not need to be changed during the growing phase.
Just a quick reminder, the Nutrient Film Technique or NFT (sometimes called the Nutrient Flow Technique) is an active hydroponic technique where plants grow in a very shallow channels with a thin stream of water that is recirculated by a pump.
The exposed roots absorb the nutrients from the film of nutrient solution. The channels tend to be slightly sloped so that the water is drained at the end and returns to the main reservoir where the nutrient content, temperature and other factors are controlled.