This waterproof mat fits neatly beneath 4 standard-size seed flats, raising the temperature of the soil anywhere from 10 to 20 degrees above that of the surrounding air. You can't get much use from it in a zero-degree room, but if you've got a chilly basement or mudroom just perfect for starting seeds, plug in this mat and off you go!
There is no need to use a thermostat with this mat, though if you want to measure the exact soil temperature (for those hard-to-start seeds!), we've got a nifty little thermostat to do the trick. And the mat includes helpful hints printed right on, so you never need root around for gardening books when facing a new seed-starting challenge!
This is the largest size of seedling heat mats, measuring 48 by 20 inches and holding 4 standard-size seed flats. If you want a smaller size, consider the 2-flat (20 by 20 inches) or single-flat (9 by 19 ½ inches) models.