When to Plant Squash in the UK
On this page
- Squash (Cucurbita moschata)
- Regional Planting Calendar
- Quick Facts
- At a Glance
- Is It Too Late to Plant Squash?
- Soil & Growing Conditions
- Growth Stages
- Harvest & Storage
- How Do You Know When to Pick Squash? Summer vs Winter
- Diseases
- Pests
- Companion Planting
- Pollination
- Winter Squash, Seed to Store
- Plan your Squash planting
- Growing Squash in another region
- References
- Frequently Asked Questions
In the UK, squash is sown early May to late June, planted out late May to late June, and is ready to harvest 60–100 days after sowing.
The short answer
- Sow
- Early May to late June
- Plant out
- Late May to late June
- Ready in
- 60–100 days
- Site
- 6+ hours of sun, soil pH 5.5–7.5
- Biggest risk
- Powdery mildew
Core growing advice on this page is checked against named horticultural sources — see References.
Squash (Cucurbita moschata)
10 sources cited · Verified
Regional Planting Calendar
| Region | Sow | Plant out |
|---|---|---|
| Southern England | early May to late June | late May to late June |
| Midlands derived | early May to late June | early June to early July |
| Northern England derived | early May to late June | early June to mid July |
| Scotland | early May to late June | early June to mid July |
Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.
Southern England - detail & sources
RHS squash guide: tender, susceptible to frost, plant out once risk has passed; courgette/squash share the RHS-stated "late May/early June" cucurbit planting-out window. Southern England mapped to the earlier end (Met Office: southern/coastal frost clears earliest).
Midlands - detail & sources
DERIVED: interpolated between Southern England and Scotland; no Midlands-specific source.
Northern England - detail & sources
DERIVED: no Northern-England-specific source; set close to but slightly ahead of Scotland per Met Office's general frost-lag pattern.
Scotland - detail & sources
RHS squash/cucurbit guidance: tender, plant out only once frost risk has passed. Scotland mapped to the later end (Met Office: further-north/higher-ground frost lingers into May, sometimes June).
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 5.5 - 7.5 |
| Sunlight | 6-10 hours direct sun |
| Germination temp | 18°C |
| Optimal growing temp | 20-30°C |
| Minimum survivable temp | 10°C |
| Time to harvest | 60-100 days |
| Soil texture | RHS: "rich, moisture-retentive but not waterlogged soil". |
| Drainage | RHS: moisture-retentive but not waterlogged, in "full sun". |
| Lifecycle | very tender warm-season annual; frost will injure top growth |
| Edible parts | fruits |
| Documented problems | 9 diseases, 12 pests |
At a Glance
Is It Too Late to Plant Squash?
Squash seed needs warmth: the RHS advises sowing indoors from mid- to late April at 18–21°C in a heated propagator or on a warm windowsill, or outdoors in late May or early June. Check the Regional Planting Calendar above for your area's window.
How long the crop then needs depends on the type: summer squash take about 35 to 45 days to mature, winter squash 80 to 120 days (University of Georgia Extension). Summer squash are picked young; winter squash are grown to maturity and stored for use into winter (RHS).
Soil & Growing Conditions
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing and germination | 0 | PLANTING DEPTH AND SPACING. Sow direct once soil reaches 65°F (18°C) or after all frost danger has passed — whichever is later. Seed goes 1–2 in (2.5–5 cm) deep, 4–6 seeds to a mound with mounds 4 ft (1.2 m) apart; thin to two plants per mound after emergence. Transplants go 2 ft apart in rows 4–6 ft apart. Utah State notes that with mulch and row covers seed or plants can be set out 2–3 weeks BEFORE the last frost, which is what lets a long-season squash finish where the season is short. Do not lay organic mulch until soil has reached 75°F — mulching cold ground keeps it cold. |
| Seedling establishment | 1 | Thin each mound to the two strongest seedlings. This is the stage cucumber beetles do disproportionate damage at, and where bacterial wilt infection takes hold, so if row cover is going on at all it goes on now — and must come off at flowering for pollination. |
| Vine growth | 3 | The plant builds the leaf area that will fund the fruit. Give it the room the spacing implies rather than crowding: airflow between plants is the main defence against the powdery and downy mildews that dominate this family, and Clemson notes powdery mildew favours dry weather with high humidity between 50 and 90°F — conditions growers often assume are safe. |
| Flowering | 6 | Utah State: "The first flowers are almost always male. Female flowers will have small fruits behind the flowers." That sequence alarms first-time growers every season and is entirely normal — there is nothing wrong with a plant producing only male flowers for the first week or two. Squash needs insects to move pollen between the two, so where bee activity is poor, hand pollination with a soft brush is the fix. |
| Fruit development | 7 | Winter squash takes 45–55 days to mature from flowering. Keep the fruit off wet soil where you can — a board or a bed of straw under a developing squash prevents the rot that follows prolonged ground contact. |
| Maturity and harvest | 8 | Utah State's test for winter squash is physical rather than visual: harvest "when the rind is hard and impervious to scratching from a fingernail". A squash cut before that point will not cure and will not store. Leave a few inches of stem attached — a squash snapped off at the shoulder rots from the wound. |
| Curing and storage | 9 | Cure, then store cool and dry at 50–55°F (10–13°C). This is the crop's whole point in a kitchen garden: properly cured and stored, it is one of the few vegetables that carries a garden through winter without a freezer. |
Harvest & Storage
How Do You Know When to Pick Squash? Summer vs Winter
The two types are picked at opposite stages. RHS: summer squashes are picked "small and tasty, with a soft skin" -- harvested young and immature, the same principle as a courgette. Winter squashes are the opposite: RHS says they should "fully ripen on the plant," and University of Maryland Extension adds that "the rinds need to be hard and firm for the squash to store well," with fruit harvested "before heavy frosts arrive."
In practice: pick summer types little and often while the skin is still soft enough to mark with a fingernail. Leave winter types on the vine as long as the season allows, until the rind hardens enough to resist a fingernail scratch and the stem starts to cork -- then cure before storing, as the gallery below explains.
Diseases
Pests
Companion Planting
Pollination
Honeybees Apis mellifera
RHS: insect pollination, mainly by honeybees; cold or poor weather reduces their activity and causes fruitlets to abort or rot at the flower end. Hand-pollination method as for courgette.
Winter Squash, Seed to Store
Plan your Squash planting
When to sow and plant Squash depends on your own frost dates. Check the UK vegetable planting calendar, or the month-by-month guides that cover Squash: January, April, June, September, October. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Squash in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
References
-
Bacterial wilt (no chemical control once infected; control cucumber beetles at first sign); powdery mildew at 50-90°F in dry weather with high humidity; downy mildew in moist conditions; gummy stem blight surviving on debris year to year, no resistant varieties, rotate to non-hosts such as corn for two or more years; anthracnose needing rainy cool weather for several days, overwintering on old vines, rotate three years; Alternaria leaf spot with bull's-eye rings at 60-90°F; Cercospora leaf spot at 79-90°F reinfecting new leaves every 7-10 days, rotate away from cucurbits 2-3 years; Fusarium wilt surviving in soil for many years with no chemical treatment.
-
Plant when soils are 65°F or after all frost danger has passed, sowing 4-6 seeds 1-2 in deep in mounds 4 ft apart and thinning to two plants; transplants 2 ft apart in rows 4-6 ft apart. With mulch and row covers, seeds or plants can be set out 2-3 weeks before the last frost. Do not apply organic mulch until soils reach 75°F. Summer squash takes 35-45 days to flowering; winter squash 45-55 days to mature from flowering. The first flowers are almost always male; female flowers carry a small fruit behind the flower. Harvest summer squash immature, 3-5 days after the flower opens, and winter squash once the rind resists a fingernail. Summer squash stores 2-4 days at 45-55°F; winter squash in cool dry conditions at 50-55°F.
10 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.
Frequently Asked Questions
How long does squash take to bear fruit?
It depends on the type: summer squash take about 35 to 45 days to mature and winter squash 80 to 120 days (University of Georgia Extension). Summer squash are picked young, while winter squash are grown to maturity and then stored (RHS).
Do you need a trellis to grow squash?
No. If you have plenty of space, trailing types can be left to sprawl over the ground; where space is tight they can be trained up a sturdy arch, pergola, wigwam of hazel stakes or strong trellis. Bush types stay reasonably compact, though they still take up about a square metre (RHS).
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
Get the UK Garden Planner →Instant PDF download · Written for UK growing conditions
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against RHS and Met Office guidance. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
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Last verified 2026-08-06
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