Never over-water again! Everything you need to start seeds and cuttings. This unique float system gives plants constant access to the ideal air-to-water ratio they need for optimum growth. The kit comes complete with a heavy-duty 21.7"x12.2"x3.1" seed tray, a 5-1/2" high dome fitted with two vents for air circulation, a 55-cell reusable floating styrofoam insert with large 1-1/2" cells that encourage deep root growth, plus 55 aerated Q-Plugs. The sponge-like Q-Plugs, composed of organic growing media, drain, yet retain water and remove from the insert easily without damage to plants.