These heat mats keep soil at a constant 10° to 20°F (6° to 11°C) above room temperature to hasten seed germination or root development in seedlings and cuttings. In fact, if you are trying to root cuttings, a heat mat is almost a necessity.
Available in three sizes: small (9" × 19" to hold one flat), medium (20" × 20" to hold two flats) and large (48" × 20" to hold at least four flats).
Effective with any non-insulated containers (please note that Styrofoam® and expanded polystyrene are poor heat conductors). Water resistant and fully ULC/UL approved.