Saving seeds from your garden vegetables lets you grow your favorites year after year without the need of purchasing new seed. Squash is one vegetable that has large, easy-to-harvest seeds. There are summer squash varieties, such as zucchini, as well as winter squashes like butternut and acorn. Squash readily crosses with other varieties in the garden, so save seed only from plants that are not grown within 50 feet of another squash variety.
Harvest summer squash for seeds when the vegetable's skin is firm and cannot be dented with a fingernail. This may be two to four weeks after you would normally harvest the squash for consuming. Harvest winter squash when you would normally harvest for eating.
Cut the squash in half lengthwise with a sharp knife. Scoop the seeds out of the two squash halves and place them in a colander.
Rinse the seeds under lukewarm running water. Remove as much of the pulp as possible.
Spread the squash seeds out on a paper towel and place them in a warm, well-ventilated place. Dry the seeds for five to seven days.
Place the seeds in a sealed plastic bag. Label the bag with the squash variety and year harvested. Store in a cool, dry place until you are ready to plant.