Due to their large size, pumpkin seeds seem particularly easy to save for planting next year. Unfortunately, pumpkins readily cross-pollinate each other, so two varieties planted too closely together can lead to an inferior seed. This can be eliminated partially by planting different varieties at least 50 feet apart, preferably with a fence or building between the beds. Collect and save seeds only from non-hybrid pumpkins as well, as hybrid plants produce sterile or inferior seeds.
Cut open the ripe pumpkin and scoop out the seeds. Separate the seeds from the pulp as much as you are able, and then place them in a colander.
Rinse the seeds off under running water. Rinse away as much of the pulp as you can, and then spread the seeds out on newspaper. Place them in a warm, dry room to dry.
Flip the seeds over one week into the drying time. Replace the newspaper if it feels damp. This ensured the seeds dry evenly on both sides and don't develop mold spots.
Brush off any remaining dried pulp from the seeds after they are finished drying, usually after two weeks. Place the seeds inside an envelope or a lidded jar.
Label the envelope or jar with the pumpkin variety and year harvested. Store the seeds in dark, cool place until ready to plant. 40 to 45 degrees Fahrenheit is the preferred temperature for seed storage.