I have some white pumpkins and I want to save the seeds and plant them next year. What should I do?
There are several varieties of white pumpkins, the most common being Cucurbita maxima ‘Lumina.’
Quoting from The American Horticultural Society’s Plant Propagation (ed. by A. Toogood, 1999, p. 300):
Leave ripe pumpkins for at least three weeks in a sunny, airy place at about 70 F to allow the seeds to mature. When the pumpkin starts to soften, cut it in half and flick out the seeds with a knife. If needed, wash off any flesh, then dry on paper towels before storing….The seeds remain viable for 5–10 years.
And quoting from Seed to Seed (by S. Ashworth, 2002, p. 29):
Home-saved seeds will retain maximum vigor when thoroughly dried and stored in a moisture-proof container…The two greatest enemies of stored seeds are high temperature and high moisture. Seeds that are stored at fluctuating temperature and moisture levels will quickly lose their ability to germinate…