I'm trying to sprout impatients in a flat using a heat mat to help achieve a target of @ 75 deg F. The flat is on one of those wire mesh shelves andwith just the flat on the mat on the shelf I can't get above mid 60s (@ room temp). I set a piece of styrofoam insulation below the flat but the temp zoomed to 90 which is not desireable either. Right now I have a sheet of butcher's paper beneath the flat and waiting to see how that does.
Any thoughts from those who have used a heat mat for seed starting?
Thanks in advance.