These heat mats keep soil at a constant 10° to 20°F above room temperature to speed germination and stimulate root growth. Complete instructions for proper use are printed right on the mat. Can be used indoors or in a greenhouse. Available in three sizes: small (9" x 19-1/2" to hold one flat), medium (20" x 20" to hold two flats) and large (48" x 20" to hold at least four flats). All sizes have 6-ft power cord. Water resistant.

Add the optional Thermostat, sold separately, for precise temperature control.