The simplest setup requires a 1-gallon, food-grade container with a top, as well as water, hydroponic solution, growing medium (like perlite or rockwool), and a mesh growing pot. In hydroponic systems, the plants require growing temperatures to be around 77-86°F for their rapid growth, making indoor gardens or greenhouses just right for year-round watercress production. Prepare a Styrofoam sheet, rock wool cubes, a bin, air stone, air hose, and an air pump. Hydroponic Lettuce and Watercress Production Lettuce and Watercress are both grown in a very similar system; the preferred system is NFT (Nutrient Film Technique). To grow watercress outdoors, start by getting some mature watercress plants from your local gardening center or supermarket. Basically, little net pots are suspended over a tank of stagnant hydroponic solution so that only the bottoms of the pots touch it. Create holes in the Styrofoam with a size that fits the size of the rock wool cubes. Fit one rock wool plug into each hole. Since watercress is an aquatic plant, growing it in a hydroponic system is a good idea. How does it work? Watercress has . Gullies are made using the 100 x 50mm rectangular hydroponic channel with … More on that later. Then, find a cool, partially shaded spot in a shallow stream or creek and mix some organic compost into the soil. Kratky method watercress for raising watercress in soil-less culture is most used and easiest. To plant this vegetable hydroponically, you can follow these steps. The NFT system uses sliding gullies inside a structure. also been grown in uncovered tanks (1 ft. deep) of non-circulating hydroponic nutrient solution, in which only about 0.1 percent of the water was required compared to Hydroponically grown watercress is produced in Hawai‘i by the nutrient film technique (NFT) where nutrient solution is kept continuously flowing. How to Grow Watercress Hydroponically.