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Squash and pumpkinsPicked September – OctoberTender · finished by the first frost

Winter squash

Cucurbita maxima / C. moschata / C. pepo

Cured for ten days and kept on a cool shelf, the September harvest feeds you until March.

Ready when: The rind is hard enough that a thumbnail cannot dent it, the skin has gone dull rather than glossy, the colour is full for the type (deep tan butternut with no green stripes, dark green buttercup, orange-flecked acorn), and the stem has started to dry and cork. Most types want 50–60 days from flowering, and a vine that is dying back on its own is telling you it is done.
How to pick: Cut, never pull: use secateurs or a knife and leave 5–10 cm (2–4 in) of stem on the fruit. A squash without its stem has an open wound and rots first. Do not carry them by the stem either. Handle like eggs — every bruise and scratch is where the rot starts — and keep the ones with any damage for eating first.
Curing: Curing hardens the rind, heals small cuts and converts starch to sugar. Leave the squash somewhere warm and airy — 27–29 °C (80–85 °F) is the figure the extension services give — for 10 to 14 days: a sunny porch or a warm room with a fan, or in the field for a week or two if the weather is dry and sunny. Acorn and delicata types are the exception: do not cure them, it shortens their life; eat them within a couple of months.
On a frost night: The vines die at the first touch of 0 °C, but the fruit underneath usually comes through a light frost unmarked. A hard freeze is different: the flesh under the rind is damaged and the squash will rot in storage instead of keeping. So on a light-frost night leave them; on a hard-freeze forecast, or any frost after the vines are already dead and no longer sheltering the fruit, bring everything in or throw blankets and tarps over the patch. Fruit that is nearly mature finishes ripening indoors; a green, thin-skinned one does not.

Where it keeps

Storing winter squash

Where	Temperature	Humidity	Keeps	How
Cool, dry room: cold room, insulated garage, basement corner	10–15 °C50–59 °F	dry	Acorn 1–2 months; butternut 2–3 months; buttercup, kabocha, hubbard 3–6 months	One layer on a shelf or slatted boards, not touching, not on a concrete floor, with air moving. Relative humidity 50–70%. Not near apples or pears, whose ethylene shortens the life. Never below 10 °C — chilled squash rots from the inside.
Spare bedroom closet, under the stairs, top of a basement stairwell	15–20 °C59–68 °F	dry	Roughly half as long as the ideal	Same rules: single layer, air space, check weekly and cook anything with a soft spot the same day. Warmer than 20 °C the flesh goes stringy and dry.

Putting it up

What to do with too many winter squash

A cured squash on a cool shelf is already preserved, which is the whole point of the crop; the pantry work comes in January when they start to turn. Then the best method is to roast or steam the flesh, mash it, cool it, and freeze the purée in 500 ml tubs with 1 cm of headspace — it keeps a year and is pie, soup and baby food on demand. What does not work, and this is the one squash rule to carry in your head, is canning purée: mashed or puréed squash or pumpkin cannot be safely canned at home by any method, because the mass is too dense for heat to reach the centre of the jar in a predictable time, and neither can squash butter. The only way squash goes in a jar is as 2.5 cm (1 in) cubes, boiled two minutes and pressure-canned — 55 minutes for 500 ml jars, 90 minutes for litre jars, at 10 psi (weighted gauge) near sea level — and mashed after opening. There is no water-bath method for any squash. Dried squash chips and leather are a good use of a dehydrator, and the seeds roast.

Curing
Two weeks of warmth and air that turn a fresh crop into a keeper.
Cold storage
The oldest method: the right cold, the right damp, and darkness.
Freezing
The fastest route and the one that keeps flavour best.
- Roasted squash and pumpkin purée, frozen →
Pressure canning
Jars heated above boiling under pressure — the only safe way to can plain vegetables.
- Pumpkin and winter squash cubes, pressure canned →
Drying
A dehydrator or a low oven; light, keeps for a year.

Freezing
Roasted squash and pumpkin purée, frozen
The safe way to put up smooth pumpkin for pie, soup and muffins — in the freezer, in the amounts your recipes call for.
A 2 kg butternut or pie pumpkin gives about 1 L of purée, four 250 ml portions · 30 minutes active
The recipe →
Pressure canning
Pumpkin and winter squash cubes, pressure canned
The only safe way to put squash in a jar: firm cubes in water, which you drain and mash the day you bake the pie.
About 9 × 500 ml (pint) jars from 4.5 kg (10 lb) of squash, or 7 × 1 L (quart) jars from 7.3 kg (16 lb) · 1¼ hours active
The recipe →

Saving seed

Crosses with its neighbours — needs isolation

Squash crosses within its species but not across species, and that is the key. Cucurbita pepo covers acorn, delicata, spaghetti squash, zucchini and most pumpkins; C. maxima covers buttercup, kabocha, hubbard and the giant pumpkins; C. moschata is butternut and its relatives. So a butternut will save true beside a buttercup and an acorn, but not beside another moschata, and your acorn is crossing with the zucchini three beds over. Grow one variety per species, isolate by 250–800 m (800 ft to ½ mile), or hand-pollinate a female flower and tape it shut. Pick the seed fruit fully mature and let it sit at least three weeks — the seeds keep maturing inside — then scoop, rinse off the strings, pick out the fat seeds and dry on a plate for two to three weeks until one snaps instead of bending. Most garden varieties are open-pollinated, but check the packet for F1.

Keeps: About 6 years.

The seed-saving guide →

Next year

Planning winter squash for next season

Cucurbit rotation — two or three years away from squash, pumpkins, cucumbers and melons. Full sun, deep rich soil, and room: vining types want 1.5–1.8 m (5–6 ft) between rows and 60–90 cm (2–3 ft) between plants, or a sturdy trellis for the small-fruited kinds. Direct sow 1–2 weeks after the last frost when the soil at 5 cm is 18 °C (65 °F); seed rots in cold soil. In zones 3–4, where 100 frost-free days is a good year, start seed indoors in large pots three weeks before planting out, transplant without disturbing the roots, and choose 85–95-day varieties — buttercup, early butternuts, delicata and most acorns ripen; a 110-day hubbard is a gamble. Row cover for the first month keeps the heat in and the beetles out.

Winter squash at a glance

Botanical name: Cucurbita maxima / C. moschata / C. pepo
Group: Squash and pumpkins
Picked: September, October
Frost: Tender: finished by the first frost.
Best put up as: curing, cold storage, freezing, pressure canning, drying
Seed: Crosses with its neighbours — needs isolation

Questions people ask about winter squash

When is winter squash ready to harvest?

When a thumbnail cannot dent the rind, the skin has gone dull, the colour is full for the type — butternut with no green left — and the stem is drying and corky. In most of southern Canada that is mid-September into October. Cut with 5–10 cm of stem and bring them in before a hard freeze; a light frost that kills the vines does not hurt the fruit.

How do you cure and store winter squash?

Cure 10–14 days somewhere warm and airy, around 27–29 °C, to harden the rind and heal nicks — except acorn and delicata, which are not cured. Then store at 10–15 °C in a dry room, single layer, not on concrete, not near apples. Butternut keeps 2–3 months, buttercup and hubbard 3–6, acorn 1–2. Check weekly and cook the soft ones first.

Can you can squash purée at home?

No, not by any method. Puréed or mashed squash and pumpkin cannot be safely home canned — the purée is too dense for heat to reach the centre of the jar reliably, and the same goes for squash butter. The only canned form is 2.5 cm cubes, pressure-canned 55 minutes for 500 ml jars or 90 minutes for litres at 10 psi near sea level. For purée, freeze it.

Can you freeze winter squash?

Yes, cooked. Roast or steam until soft, scoop, mash, cool quickly, and pack in 500 ml tubs or bags with 1 cm headspace; it keeps a year. Raw cubes can be blanched 3 minutes and frozen but come back soft, so purée is the better use of freezer space. A frozen 500 ml tub is one pie or one pot of soup.

Is winter squash frost hardy?

The plant is not — vines die at 0 °C — but the fruit takes a light frost without harm, especially while the leaves still shelter it. A hard freeze damages the flesh and the squash will not store. Bring them in or cover them when a hard freeze is forecast, or any time after the vines are dead.

How do I save squash seeds?

Only one variety per species — pepo (acorn, delicata, zucchini, most pumpkins), maxima (buttercup, kabocha, hubbard) and moschata (butternut) do not cross with each other but cross freely within each group. Let the seed fruit sit three weeks after harvest, scoop, rinse, keep the fat seeds, dry two to three weeks. Good for about six years.

What can kids do with winter squash?

Harvest day is theirs: they can thumbnail-test every fruit, carry the small ones in a wagon (by the body, never the stem), and line them up by kind to cure. In the kitchen, scooping and sorting seeds is a good counting job, and roasted seeds are the reward. A hubbard needs a grown-up and a heavy knife; a delicata a six-year-old can cut with help.

Your own frost dates

When does this come in where you are?

Enter a town, postal code or ZIP and the garden year, the frost watch and this week’s guide are built from your own weather.

Also in squash and pumpkins

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Squash and pumpkinsPicked Sep–Oct
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Checked against these sources · last reviewed October 2026

Harvest months are typical for zones 4–6 and move by weeks north and south. Storage figures are for the ideal; a house without a cold room will get the shorter end of each range.