May 8, Before you can grow pumpkin seeds, you need to know when to plant pumpkin seeds. When you plant your pumpkins depends on what you. Jul 8, Yesterday when I found this method, I tried sanding one edge off each of ten pumpkin seeds. The previous two attempts at germinating these. Feb 12, Pumpkin Seed Starting: Sow pumpkins in the garden in spring when all danger of frost has passed and the soil temperature has reached 65°F.