This picture shows tobacco transplants that are grown in a float bed in a small plastic-covered greenhouse. Tobbaco is not a vegetable but this picture illustrates how float bed technology can be used to grow vegetable tranplants. The trays are constructed of polystyrene so they can float on a shallow bed of nutrient solution or water. The green residue on the side of the tray is caused by algae and shows the water line. Algae tends to grow anywhere there is sunlight so float beds must be covered at all times. Roots will grow through the bottom of the trays in the water. These roots may be lost when the plants are pulled from the trays. This does not hurt tobacco but more delicate plants may be damaged. There is increased interest in growing vegetable transplants using float beds or a modified system called ebb-and-flood where water is periodically drained from the beds to prevent plants from growing too rapidly.