Replanting squash seeds from saved seeds requires planning. It begins when you originally save the seeds. Squash readily cross pollinates with other similar varieties in the garden, so saved seeds may not be true to the plant they are collected from. Planting only one variety of squash in a given period minimizes this risk. Saved seeds may also have lower germination rates, so replanting may require heavier seeding. Plan both at the time of harvest and when you sow in order to have a successful squash crop.
Check germination rates before planting the seeds. Dampen a paper towel and wrap five seeds in the towel. Place inside a plastic bag and seal. Place in a warm place for 14 days to germinate. If most of the seeds germinate your rate is good, if only one or two germinate plant twice as many seeds as plants desired.
Fill seed starting pots with a quality seed starting soil. Moisten the soil evenly throughout.
Sow seeds of summer squashes half an inch deep in the center of the pot. Sow winter squash seeds to a depth twice that of their width.
Cover the top of the pot with plastic wrap and place in a 65 to 70 degree Fahrenheit room to germinate. Germination takes approximately 14 days for most varieties.
Remove the plastic wrap once sprouts appear and place the pots in a sunny window or under grow lights. Place grow lights three inches above the top of the plants.
Transplant summer and winter squash outside in spring, once soil temperatures have warmed to 70 degrees Fahrenheit. Keep the soil moist at all times.