Just a quick idea I just had to keep seeds warm without using a heat mat. Sittin watchin TV today, my cable box was acting up on me..so I went over to my tv stand, opened the tinted glass, to check the cords... and the top of the box of my cable box is fairly warm. This box usually stays on when I turn off my tv...so I thought about it and the old paper towel in a pie plate on this would propably be ideal....food for thought 
