Growing squash, pumpkins & courgettes
The squash family are the great sprawlers of summer — big-leaved, bold and astonishingly generous once they get going. A single courgette plant can feed you for weeks; a winter squash vine can fill a corner and hand you a larder of soups for the cold months. They ask for just three things in return: warmth, room, and more food and water than you'd think.
This is the family overview — for sowing dates and varieties of each, follow the links through to its own page.
One family, summer to winter
From courgettes you pick small and often to pumpkins you leave to swell all season, the cucurbits give you something from midsummer right through to the depths of winter from the store.
The generous one — two or three plants will feed a street. Pick small and often through summer; the more you cut, the more they crop.
Patty pans, crooknecks and the like — grown and eaten young like courgettes, but in lovely shapes and colours.
Butternut, crown prince, kabocha — left to ripen fully, then cured to store for months of soups and roasts.
From little eating types to the great orange show-offs. Hungry, thirsty and need a long, warm season to swell.
Warmth, room and plenty of muck
Squash are tender, so there's no rushing them: sow indoors in mid- to late spring, two seeds on their edge in a pot, and don't plant out until all danger of frost has passed and the soil is warm. They grow fast once they're away, so a fresh start in early summer still has time to crop.
These are hungry, thirsty plants. Plant them on a barrowload of well-rotted manure or compost — many growers plant straight onto the compost heap — and water generously and deeply, at the roots, all summer. Give them room, too: a courgette wants a square metre to itself, a pumpkin far more. Crowd them and you get mildew and sulks.
Pollination — where most crops are won or lost
Here's the thing that catches everyone out: squash carry separate male and female flowers, and a bee has to carry pollen from one to the other before a fruit will swell. The female flowers are the ones with a tiny fruit already formed behind them; the males sit on plain thin stalks. A poorly pollinated female sets a little fruit that yellows and rots at the tip instead of growing — the classic “why are my courgettes rotting?” problem.
So the single most valuable thing you can do is bring in the bees: plant borage, nasturtiums and calendula nearby (see companion plants for courgettes & squash). In cool, dull or early-season weather when bees are scarce, do their job yourself: pick a male flower, strip the petals, and dab its pollen into the centre of the female flowers in the cool of the morning. It takes seconds and makes all the difference.
Picking, and curing for the winter store
Pick courgettes and summer squash small and often— the moment you let one swell into a marrow, the plant eases off cropping. A glut is the courgette grower's rite of passage; pick every few days and share the surplus.
Winter squash and pumpkins are the opposite: leave them on the vine to colour up fully and let the stem begin to cork, ideally before the first frost. Then curethem — a fortnight somewhere warm and dry to harden the skins. Cured and stored somewhere cool, dry and airy, a good winter squash keeps for months, the slow reward of the whole sprawling summer. A length of weed-suppressing membrane under the swelling fruits keeps them clean and off the damp soil as they ripen.
Common questions
Why are my courgettes rotting when small?
Usually poor pollination — an unpollinated female flower sets a tiny fruit that yellows and rots at the tip instead of swelling. Bring in pollinators with borage and nasturtiums nearby, and in cool weather hand-pollinate by dabbing pollen from a male flower into the females (the ones with a tiny fruit behind them).
How do I get more pumpkins and squash to set?
Feed the bees and, if needed, do their job. Plant pollinator flowers nearby and hand-pollinate in the morning: brush pollen from a male flower onto each female. For big pumpkins, limit each plant to one or two fruits so all its energy goes into them.
What is the white powder on my courgette leaves?
Powdery mildew — a near-inevitable late-summer fungus. It rarely kills an established plant. Slow it by watering the soil not the leaves, spacing plants for airflow, and removing the worst leaves. A fresh plant sown in early summer often crops on cleanly.
How do you store winter squash and pumpkins?
Leave them to colour fully and the stem to cork, ideally before frost. Then cure them a couple of weeks somewhere warm and dry to harden the skins. Kept cool, dry and airy, good winter squash stores for months.