Begrow 35mm x 40mm Stone Wool Starter Plugs (2500pcs/Case)Begrow stone wool plug is the first stage in hi tech hydroponic farming of vegetables, flowers and other plants cultivation. Seeds are germinated in such plugs. Then the grown sprouts are transplanted into the stone wool cubes provided with special holes together with these plugs. The key advantage of our stone wool plugs is their structural uniformity and density. It allows to maintain uniform water and nutrient solution as well as stable pH level.