With pumpkin seed starting time next month it is a good time now to start practicing your seed starting techniques. No reason to lose a good seed to poor techniques or a poor seed starting mix. For the last few years I've been using ProMix BX for my seed starting mix. I amend that with some earthworm casting from my own bins (about 1 cup) along with some myco and a little Azos at the bottom third of the pot. For the full seed starting procedure look for my posts in April in previous years.
Late this fall I did a test planting with a soil less mixture that seemed pretty promising. I knew other growers had amended their soil with a similar product from the same company and had good results so I wanted to give it a try. Everything come up nicely but three weeks later all three of the plants I had started quickly turned yellow. I'm not sure what caused that but my suspicion is that the soil less mixture had a problem with it. I won't be using it again. You don't want the first month of the season to start with dead plants.