Drop this lid onto the 52 x 52cm mini ebb and flow tray and you have a small hydroponic bed. It measures 7 x 53 x 53cm, with planting holes 7.9cm wide. Roots dangle into a shallow film of nutrient water below, the method growers call shallow water culture.
Lettuce, basil and other salad herbs love it, because they grow fast and stay small. Sit a net pot in each hole to hold the plant steady over the water. The lid works with the mini tray, and you can buy a full setup with tank, pump and grow table if you want the lot.