How to tell when your squash or pumpkin is ready to harvest

September is the month when pumpkins and squash start driving you a little bit mad.

They look almost done. The colour is sort of there, but not quite right yet. The stem is still green. Or is it already turning brown? Then the first frost warning comes up on your weather app and you start wondering whether you should just harvest everything now before something goes wrong.

Not so fast. Or maybe yes — it depends entirely on what your squash is showing you.

The four reliable signs of ripeness

No single sign is enough on its own. But when you see all four together, the squash is ready.

1. The stem has corked over and turned brown

A green, juicy-looking stem means: not yet. A woody, dark brown or grey stem that feels dry — this is the single most reliable indicator. On Hokkaido pumpkins the corking is very visible. On butternut squash it can be subtler.

If the stem is still fresh green, the squash usually has another two to four weeks ahead of it.

2. The skin resists your thumbnail

Press your thumbnail firmly against the skin. Not a scratch — just pressure. On an unripe squash the skin gives slightly or leaves a dent. On a ripe squash nothing happens. The skin is as hard as wood.

This test works on all varieties, and it doesn't allow for misinterpretation: if the skin yields, the squash isn't done.

3. The colour is fully developed and matte

Ripe squash doesn't shine. A glossy Hokkaido is usually not quite there yet. A deep, rich orange-red with a matte finish is what you're looking for.

For green or grey varieties — Crown Prince, Delicata, some butternuts — the colour barely changes, so you have to rely more on the stem and skin. But the same principle applies: a glossy surface is an early sign, a matte one is ripeness.

4. The hollow knock

Knock the skin with your knuckle, as you would a watermelon. An unripe squash sounds dull and solid. A ripe squash sounds hollow, almost drum-like.

This is the most subjective of the four signs, and at first every squash sounds the same. But after a season or two you hear the difference very clearly. Practice helps.

What happens in a frost

Squash can tolerate a light frost — one or two degrees below zero, brief and with cloud cover. This usually does no harm as long as the skin is intact.

What they cannot tolerate is a sustained, hard freeze. Temperatures below about minus four to minus five Celsius for several hours can damage the squash from inside, even if the skin shows nothing. Ice crystals form in the flesh and damage it. The squash is still edible, but it won't store well.

The rule of thumb for Central European conditions: have everything harvested before the first ground frost, for anything that isn't clearly still unripe. In most years that gives you until mid to late October.

When to harvest earlier than planned

If a squash starts to rot on its underside — a soft, discoloured patch where it sits on the ground — harvest it immediately. A slightly early squash you eat now is better than a half-rotten one you throw away.

This happens most often when squash sit on damp soil. Less common in raised beds, but not impossible. If you see water pooling under the squash, slip a piece of wood or some fleece underneath.

After harvesting: curing is everything

A freshly harvested squash is not yet ready to store. It needs a curing period — time to harden off at warmth.

Optimal conditions: ten to fourteen days at twenty to thirty degrees Celsius, somewhere dry and well-ventilated. A sunny windowsill, a garden table, a shelf in the greenhouse. During this time the skin dries out further, small surface wounds heal, and the squash builds up more sugar.

A squash you haven't cured might keep for two months. A properly cured Hokkaido or butternut, stored cool and dry, will easily last five to six months — right through until March, April, sometimes even May.

Storage after curing:

• Temperature: ten to fifteen degrees Celsius
• Never cold storage below eight degrees — this causes chilling injury
• Store individually, not stacked — pressure points become rot spots
• Always keep the stem on — it's the squash's natural seal

What Mrs Schneider did

Mrs Schneider planted two squash seedlings into her raised bed in mid-April — one Hokkaido, one butternut. The Hokkaido is now a bright orange-red and the stem feels dry. The butternut is still pale, almost beige, and the stem still has a trace of green.

I told her: take the Hokkaido now, leave the butternut another ten days.

She took the Hokkaido, put it on the windowsill, and three weeks later we both had a very good squash soup.

🦔 Stachi