Another possibility for starting your pumpkin plants- for the last 6 years I have started my giant pumpkins in 4 inch peat pots in an old refrigerator. A 25 watt light bulb located under the shelving provides a constant 85 degrees and a humid environment for germination in a few days. It has worked great for me. Once the ground starts to bulge up or the plants start to pop through, remove them immediately or the plants grow tall and spindly searching for light. Good luck.