Harold Eddleman Ph.D said: > I use several systems. Mainly I have 3/4 inch black plastic pipe >coiled on my greenhouse benches spaced 6 inches apart. During night I >cover with floating row cover (Remay, etc) to help hold heat on them >plants. I use one 400 watt HPS (high pressure sodium) light per 5.5 x 11 >foot bench. Hey, I hate to be dense, but what are you putting in that 3/4 inch black plastic pipe? More hot water? Is this in a greenhouse or in your house! And, what medium do you have the sweetpotato rooted in? And, did it originally come from the grocery store? Thanks -Allan Balliett Claymont Farm Charles Town, WV csa@Claymont.org