the heat mat will be set up on top of an insulating piece of foam core in my cold basement. It's usually 50 - 60 degrees down there

Then the heat mat is going to be trying to heat your whole basement and will quickly burn out. It is triggered by ambient temperature.

Even if you buy the thermostat control for the mat it still need to be in a confined enclosure of some sort, insulated from the rest of the basement.

Check some of the other posts here about using heat mats to see what others have used to create a temporary enclosure to contain the heat. Even a large box or a small tent made from plastic can make a big difference.

Dave

Thank you...I will do that!

i want to build a frame to start seed outside. I plan to erect a small structure that will heat easily and equal across the growth platform.Using what ever is handy (I am retired and on limited income).The structure will be 8 foot long and 3 foot high and 3 foot wide the out sides will be used sheet iron covered inside with batted insulation the "heat tunnel" will be some sheet insulation I was given. I will have a flat piece of material covering the three segments with an entrance at the far end from heat source blowing down the "heat tunnel" exiting and returning up a 2 inch space between first material and black painted sheet iron.The top will have raised edges and lined with a plastic material covered with old blankets burlap or other to hold water I will have stiff wire bowed to cover all with adjustable heights to limit space above seed pots to aid in heating the soil. I will cover them with black material until seed sprouted.This structure will be placed in an open area with wind protection and plenty of sun am I wasting my time? Please e mail me at johnwm21@verizon.net with your comments btw the heat process will be much like a meat smoker where heat will be channeled to far end and then bought back to heat source via another small channel and plants will be watered by capillary action from the bottom of the top pan. Only a test run this year to see if applicable
johngreenhand

You say you are GOING to buy a fluorescent light? I'm assuming you didn't have one before. That and that alone will give you leggy spindly weak seedlings.
Between the heat mat and the lights you will see a world of difference. Good luck and happy growing!

Oh, definitely, we're getting a fluorescent light! Fingers crossed that everything will work!