hey boed, i've never used a heating matt..started 9 out of ten seeds. the only oddball just wouldnt open, and i tried everything other than squishing the little sucker. Started all in my basement which is always below 70f. Drop them in a shot glass with 1/2 inch of water,soak for 8-15 hrs,then to a plate/paper towel/ set the plate on top of my modem or wifi router cause their always running and a little warm lol. make sure towel doesnt dry out and you should see sprouts in two days. good luck.