There's something satisfying about growing next year's garden from seeds you saved yourself. And when it comes to squash, the process is surprisingly simple.
Whether you're growing zucchini in a backyard garden or preparing a winter squash for supper, saving a handful of seeds can provide the beginnings of another growing season.
At Bucktown Seed Company, we grow several squash varieties for seed on our small Certified Naturally Grown seed-production plot in Chester County, Pennsylvania. Among them are Genovese Zucchini, Golden Zucchini, and Pennsylvania Dutch Crookneck winter squash.
While summer and winter squash require slightly different approaches to harvesting mature seeds, the cleaning, drying, and storage processes are much the same.
Why Save Your Own Squash Seeds?
Squash is one of the more rewarding crops for beginning seed savers. A single mature fruit can contain dozens, sometimes hundreds, of seeds, and you don't need specialized equipment to collect them.
Saving seeds also allows you to continue growing favorite open-pollinated varieties year after year.
Over time, selecting seeds from healthy, productive plants that perform well in your garden can help maintain a population suited to your particular growing conditions.
The important thing is to start with open-pollinated varieties and understand a little about how squash plants cross-pollinate.
Summer Squash vs. Winter Squash: When Are Seeds Ready?
The biggest difference between saving seeds from summer and winter squash is when the fruit reaches maturity.
Summer squash, including zucchini, is normally harvested while young and tender. At this stage, the seeds inside are still immature. To save viable seeds, you'll need to leave a few fruits on the plant much longer.
Winter squash, including butternut and Pennsylvania Dutch Crookneck, is typically harvested after the fruit has fully matured. That means the seeds inside are often ready to save when you're preparing the squash for cooking.
Both types benefit from fully mature fruit, and allowing harvested squash additional time to ripen before extracting seeds can improve seed development.
How to Save Seeds From Summer Squash and Zucchini
If you've ever overlooked a zucchini in the garden, you've probably discovered just how large these fruits can become. That's exactly what you're looking for when saving seed.
1. Let a Few Squash Grow to Full Maturity
Choose a healthy, productive plant and leave one or two fruits on the vine well beyond their normal eating size.
As the squash matures, it will become considerably larger, its rind will harden, and its color may change. Depending on the variety, a mature zucchini might turn yellow, orange, or another color.
At Bucktown, we allow our Genovese and Golden Zucchini to reach full maturity before harvesting them for seed.
2. Harvest and Extract the Seeds
Once the rind is hard and the fruit has reached full maturity, harvest the squash. If the fruit is healthy, allowing it to rest in a protected location for a few additional weeks can help the seeds finish developing.
Cut the squash open carefully and scoop out the seeds along with the surrounding pulp.
3. Wash and Dry the Seeds
Place the seeds in a bowl or bucket of water and gently work them free from the pulp.
Rinse them thoroughly, then spread them in a single layer on a screen, coffee filter, or other suitable drying surface.
Keep the seeds in a well-ventilated location away from direct sunlight and excessive heat until completely dry.
How to Save Seeds From Winter Squash
Saving seeds from winter squash is even easier because the fruit is usually harvested at maturity.
The next time you're preparing a fully mature butternut, Pennsylvania Dutch Crookneck, or another winter squash for a favorite recipe, consider setting aside some of the seeds rather than sending them to the compost pile.
- Choose a mature squash. Select a healthy fruit from an open-pollinated variety.
- Scoop out the seeds. When cutting the squash for cooking, separate the seeds from the stringy pulp.
- Rinse thoroughly. Wash away any remaining flesh or debris.
- Spread out to dry. Arrange the seeds in a single layer on a coffee filter, screen, or paper towel.
- Store when completely dry. Once thoroughly dried, place the seeds in a labeled envelope or suitable storage container.
Paper towels work for small batches, although seeds may stick to the fibers. Coffee filters or screens are often easier to use.
At Bucktown, we grow Pennsylvania Dutch Crookneck, a historic winter squash with a distinctive curved neck and rich orange flesh. When processing mature fruits for seed, we scoop out the seeds, separate them from the pulp, wash them, and spread them out to dry.
A helpful tip: If you're saving seeds from winter squash purchased at a grocery store or farmers market, they may germinate successfully, but there's no guarantee the resulting plants will resemble the original fruit. That depends on the variety and how it was pollinated.
Understanding Squash Cross-Pollination
Here's where seed saving becomes a little more interesting.
Squash plants produce separate male and female flowers, and bees carry pollen between them. When two varieties of the same squash species grow near one another, they can cross-pollinate.
The squash you harvest that season will still look and taste as expected, but seeds from a crossed fruit may produce something quite different the following year.
Not All Squash Varieties Cross With One Another
Most commonly grown squash belong to four species:
- Cucurbita pepo: Zucchini, yellow summer squash, acorn squash, delicata.
- Cucurbita maxima: Hubbard, kabocha, buttercup.
- Cucurbita moschata: Butternut, Pennsylvania Dutch Crookneck.
- Cucurbita argyrosperma: Many cushaw squash varieties.
Varieties within the same species can readily cross-pollinate. Different species generally do not, although rare exceptions exist.
An Example From Our Seed-Production Plot
We've grown Pennsylvania Dutch Crookneck winter squash and Genovese Zucchini in the same field during the same season without needing to isolate them from each other.
That's because Pennsylvania Dutch Crookneck belongs to Cucurbita moschata, while Genovese Zucchini belongs to Cucurbita pepo. These two species generally don't cross-pollinate.
However, Genovese Zucchini and Golden Zucchini both belong to Cucurbita pepo. Growing those varieties together for seed requires additional precautions to prevent unwanted crossing.
For home gardeners, the lesson is simple: Before saving seeds from multiple squash varieties, find out which species they belong to.
If you're growing just one variety of a particular species, seed saving may be straightforward, provided there aren't other compatible squash varieties flowering nearby—including in neighboring gardens.
If you're growing several varieties of the same species, controlled hand-pollination or adequate isolation can help maintain true-to-type seeds.
For gardeners who simply enjoy experimenting, seeds from crossed varieties can still produce interesting squash. Just understand that the results may be unpredictable.
How to Store Squash Seeds for Next Season
Once your seeds are completely dry, proper storage will help preserve their viability.
Keep them in a cool, dry, dark location, away from moisture and fluctuating temperatures.
Be sure to label each batch with the variety name and harvest year. It's surprisingly easy to forget which seeds came from which squash once everything has been cleaned and dried.
Under favorable storage conditions, squash seeds can remain viable for several years—often five or six, sometimes longer.
For more advice, read our guide to storing seeds for future use.
Frequently Asked Questions About Saving Squash Seeds
Can I save seeds from a zucchini I picked for eating?
Usually not. Zucchini harvested at normal eating size contains immature seeds. Leave a few fruits on the plant until they're much larger and the rind has hardened.
Do squash seeds need to be fermented?
No. Unlike tomatoes, squash seeds generally don't require fermentation. Removing the pulp, rinsing, and thoroughly drying the seeds is sufficient.
Can zucchini and pumpkins cross-pollinate?
Yes, depending on the species. Many pumpkins belong to Cucurbita pepo, the same species as zucchini, and can cross-pollinate with them.
Can I save seeds from just one squash?
Yes. A single mature squash can provide plenty of viable seeds. However, saving seeds from multiple healthy plants is better for maintaining a variety's genetic diversity over time.
Looking for More Growing Advice?
Explore our Growing Guides for practical advice on planting, spacing, growing conditions, and caring for vegetables, herbs, and flowers throughout the growing season.
A Garden That Continues
Seed saving doesn't require a large garden, expensive equipment, or years of experience.
Sometimes it's as simple as allowing a zucchini to grow a little longer or setting aside a handful of seeds while preparing winter squash for dinner.
With a little care, those seeds can become next year's plants—and perhaps the beginning of a seed-saving tradition of your own.
At Bucktown, we believe there's something worth preserving in that simple cycle of growing, harvesting, and planting again.
