This is the one week of the year when nearly everyone has a pumpkin sitting on the porch and a bowl of slimy seeds on the kitchen counter. Before that bowl goes in the compost, it's worth asking: could these seeds grow next year's patch?
Often the answer is yes. Pumpkin and winter squash seed is some of the easiest seed a home gardener can save. It's big, simple to clean, and stays viable for five years or more. Here's how to tell whether your seed will grow true, how to save it, and how to store the squash you're keeping for the kitchen.
First question: will it grow true?
Two things decide whether saved squash seed gives you the same squash next year.
1. Is it an heirloom (open-pollinated) variety? Many grocery-store and pumpkin-patch pumpkins are hybrids. Seed from a hybrid will sprout, but the plants are a grab bag and rarely match the parent. If you grew an heirloom like Connecticut Field pumpkin, the classic jack-o'-lantern variety grown since colonial times, you're starting in good shape.
2. Did it cross with another squash? Squash are pollinated by bees, which happily carry pollen from plant to plant. Squash only cross within the same species, so it helps to know which species you grew:
- Cucurbita pepo: most field pumpkins (including Connecticut Field), acorn squash like Table Queen, spaghetti squash, zucchini, yellow summer squash, and most ornamental gourds.
- Cucurbita maxima: buttercup types like Burgess Buttercup, Hubbard, and giant pumpkins.
- Cucurbita moschata: butternut and many cheese pumpkins.
A pepo will never cross with a maxima, so if the only pepo in your garden was your pumpkin and the only maxima was your buttercup, both are likely to come true. But if you grew pumpkins next to zucchini and acorn squash, which are all pepo, this year's seed may produce some interesting surprises. Neighbors' gardens count too; bees travel, and seed savers typically recommend half a mile or more between varieties of the same species.
Not sure? Save the seed anyway and treat next year as an experiment. Just don't count on it for your main planting.
Pick the right fruit
- Fully mature fruit only. Pumpkins and winter squash should be fully colored with a hard rind you can't dent with a fingernail. Seed from immature fruit is often thin and won't sprout.
- Let it sit a while. Seed keeps maturing after harvest. If you can, let the fruit rest for three or four weeks before you cut it open for seed. Your porch pumpkin, if it wasn't carved, is doing exactly that right now.
- Choose your best plant. Save from the healthiest, most productive vine with the best-tasting fruit. Over the years, that's how heirlooms got good in the first place.
Carving this week? Scoop the seeds the day you carve. Don't wait until the jack-o'-lantern has been sitting out for a week and starting to soften.
How to clean and dry squash seed
- Scoop the seeds and stringy pulp into a bowl.
- Rinse and rub them in a colander under running water, pulling off the strings with your fingers.
- Float test. Drop the cleaned seeds in a bowl of water. Plump, heavy seeds sink or sit low; flat, hollow ones float. Skim off and discard the floaters.
- Dry. Spread the seeds in a single layer on a plate, a cookie sheet, or a window screen. Skip paper towels; the seeds stick to them. Keep them somewhere airy and out of direct sun, and stir once a day.
- Check that they're dry. After one to three weeks, a dry seed snaps when you bend it instead of flexing. Only then should it go into storage.
- Label and store in a paper envelope inside a sealed jar, somewhere cool, dry, and dark. Write the variety and year on the envelope. You'll forget, and pepo seeds all look alike.
Have extra? The leftover seeds from a field pumpkin roast up beautifully with a little oil and salt at 325°F for about 20 to 30 minutes.
Curing and storing the squash you're eating
Seed saving aside, a well-stored winter squash can feed you for months. The trick is knowing which ones need curing.
Cure: pumpkins, buttercup, Hubbard, and butternut. Keep them somewhere warm (around 80 to 85°F) with good air flow for about 10 days. This hardens the rind and heals small scratches. A sunny spot indoors or a warm room works fine.
Don't cure: acorn squash. Warm curing temperatures can make acorn types turn stringy and lose quality faster. Move them straight to storage.
Store: all winter squash like it cool and fairly dry, ideally 50 to 55°F with moderate humidity. A basement, cool closet, or unheated spare room is ideal. Avoid the fridge, which is too cold and damp for long storage. Keep the fruits in a single layer, not touching, and check them every week or two for soft spots.
Eat in this order:
- Acorn and spaghetti squash first. They keep roughly one to two months.
- Pumpkins next, at about two to three months.
- Buttercup last. It keeps about three months and gets sweeter after a few weeks in storage.
Planning next year's patch
If you want seed you can count on next fall, plan for it now. Grow only one variety of each species, or plan to hand-pollinate: tape a female flower shut the evening before it opens, pollinate it the next morning with a male flower from the same variety, then tape it shut again and tie a ribbon on the stem so you know which fruit to save.
And if your saved seed turns out to be a mystery cross, no harm done. Fresh packets of Connecticut Field, Table Queen acorn, Burgess Buttercup, and spaghetti squash are packed in-house and ready when you are.
Happy Halloween, and happy seed saving.