Zucchini plants (Cucurbita pepo), those prolific producers of summer squash, grow most readily from seed sown directly in the garden. Saving your own seed for yearly planting truly gives you an unending supply of the summer vegetable year after year. Zucchini seeds only mature when the fruit reaches full maturity several weeks after it passes the edible stage. Leave a few squash to set seeds on your healthiest and most productive plants. The seeds often have the same healthy traits as the parent plants.
Allow the zucchini to continue growing on the plant until the fruits become large and the skin hardens. Pick the zucchini when you can dent its skin with a fingernail.
Cut the zucchini in half lengthwise with a clean knife. Scoop the seeds and pulp from the center of the zucchini with a spoon.
Place the seeds and pulp in a colander. Rinse the seeds with lukewarm water until the pulp is completely removed.
Spread the seeds in a single layer on a tray covered in wax paper. Set the tray in a well-ventilated area and allow the seeds to dry. Dry the seeds for about one week, stirring them daily so they dry evenly on both sides.
Place the dried seeds in an airtight storage container. Label the container with the zucchini variety and harvest year. Store the seeds in a cool, dark place until spring planting.