When to Plant Cucumbers in the UK
On this page
- Cucumber (Cucumis sativus)
- Watch: Growing Cucumbers at Home
- Quick Facts
- At a Glance
- Regional Planting Calendar
- Greenhouse or Outdoors? The Trick to Growing Cucumbers
- Growth Stages
- Soil & Growing Conditions
- Harvest & Storage
- The Tomato-Cucumber Myth -- and What Coffee Grounds A...
- Diseases
- Pests
- Cucumbers, Seed to Harvest
- Plan your Cucumbers planting
- Growing Cucumber in another region
- References
- Frequently Asked Questions
In the UK, cucumbers are sown early February to late April, planted out late May to late June, and are ready to harvest 50–70 days after sowing.
Timing is the decision that matters most in the UK: there are 4 separate regional planting out windows, ranging from late May in Southern England to early June in Scotland.
The short answer
- Sow
- Early February to late April
- Plant out
- Late May to late June
- Ready in
- 50–70 days
- Site
- 6+ hours of sun, soil pH 6–6.5
- Biggest risk
- Powdery mildew
Core growing advice on this page is checked against named horticultural sources — see References.
Cucumber (Cucumis sativus)
9 sources cited · Verified
Watch: Growing Cucumbers at Home
A short SoilCommander video on growing your own vegetables at home, including cucumbers — a quick look at getting crops going in a small space.
Quick Facts
At a Glance
Regional Planting Calendar
| Region | Sow | Plant out |
|---|---|---|
| Southern England | early February to late April | late May to late June |
| Midlands derived | early February to late April | early June to early July |
| Northern England derived | early February to late April | early June to mid July |
| Scotland | early February to late April | 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: outdoor cucumbers are "tender... for growing... in a warm sunny site outdoors" and are "grown in a similar way to their fellow cucurbits" (courgettes/squash/pumpkins) -- which RHS's greenhouse-growing guide places outdoors "in early summer" once frost has passed. 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: outdoor cucumbers are tender cucurbits, planted 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).
Greenhouse or Outdoors? The Trick to Growing Cucumbers
Both work, but they're different plants in practice. Greenhouse (indoor) types are smooth-skinned and all-female, cropping earlier and more heavily under cover; outdoor "ridge" types have tougher, often knobbly skins and are bred to tolerate the cooler, more variable conditions outside. Buy seed labelled for the situation you're growing in -- an indoor variety sown outdoors won't fruit as reliably.
The real trick RHS keeps coming back to is consistency: sow under cover at 21°C, don't plant out until frost risk has fully passed, and then water evenly -- erratic watering, more than almost anything else, is what causes bitter fruit and blossom end rot.
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing & Germination | 0 | Cucumbers are almost always started under cover. SOWING DEPTH: sow one seed 1-2cm (half to three-quarter inch) deep in the centre of a 10cm pot of peat-free compost, placing the seed on its edge (side). TIMING: heated greenhouse mid-February to mid-March; unheated greenhouse or polytunnel in April; outdoor (ridge) types in late April, or sown direct into their final positions in late May/early June (up to three seeds per station, thinned to the strongest). Germinate at about 21°C (70°F) in a heated propagator or a plastic bag on a warm windowsill; seedlings appear in one to two weeks. Never sow cold or early outdoors - the crop is frost-tender. |
| Planting Out & Training | 3 | Harden off greenhouse plants before moving to their final spot from late May; plant outdoor (ridge) cucumbers out only from early June once local temperatures are reliably above 12°C (53°F) and all frost has passed. SPACING: set plants 30cm (1ft) apart, or one per container at least 30cm wide and deep. Train the climbing stems up tall bamboo canes, strings or a wigwam, tying them in as they establish. Keep plants warm and sheltered; in the greenhouse aim for 18-25°C and raise humidity in hot spells. |
| Flowering & Pollination | 6 | Cucumbers carry separate male and female flowers (the female has a tiny fruit behind the bloom). GREENHOUSE all-female F1 types set seedless fruit without pollination - remove any occasional male flowers, as pollination makes the fruit bitter and misshapen. RIDGE (outdoor) types need their male flowers for insect pollination, so leave them. Pinch out (stop) the growing tips to steer the plant: in the greenhouse pinch the main stem at the roof and side-shoots two leaves beyond a female flower; outdoors pinch the main stem once the plant has seven leaves. Begin high-potash (tomato) feeding as flowering starts. |
| Fruit Development | 7 | Fertilised (or, on all-female types, unpollinated) female flowers swell into fruit. This is the thirstiest stage: keep the soil or compost evenly moist, watering at the base to avoid wetting the leaves, and daily in hot weather - erratic watering causes bitter or misshapen fruit. Feed every 10-14 days with a high-potash liquid feed. Support heavy fruits and keep picking so the plant channels energy into new cucumbers rather than seed. |
| Harvest | 8 | Pick fruits young, while uniformly green and firm with a slightly rounded tip, before they yellow or swell (over-mature and yellowing cucumbers turn bitter and stop the plant cropping). Sizes at picking: mini types about 8cm (3in), small-fruited about 15cm (6in), full-sized 20-25cm (8-10in). Cut the stem cleanly with a knife or secateurs rather than pulling, and harvest every few days - regular picking keeps more fruit coming, from mid-summer to mid-autumn under glass and over a shorter season outdoors. Typical time from sowing to first harvest is about 50-70 days. Store cut cucumbers cool (about 7-10°C) and humid for around a week. |
Soil & Growing Conditions
Harvest & Storage
The Tomato-Cucumber Myth -- and What Coffee Grounds Actually Do
Can tomatoes and cucumbers be planted together? Yes -- checked directly against Ask Extension's own companion-planting guidance, which finds no garden-planting incompatibility between them at all: "You can, but you need to make sure that you leave enough room... so they don't deprive each other of sun, water and nutrients." The "can't be planted together" idea most likely comes from a real but different fact: Purdue University's Vegetable Crops Hotline warns to "avoid stor[ing] cucumbers together with ethylene producing fruit such as ripening tomatoes" once harvested, since cucumbers are unusually ethylene-sensitive and spoil faster near them. That's a fridge rule, not a garden one -- the two plants grow fine side by side.
What do coffee grounds do? Less than the folklore suggests. Washington State University Extension tested this directly: used grounds are close to pH-neutral, not acidic as widely believed, and "fresh grounds are demonstrably phytotoxic to a variety of plants" -- WSU records "reduced seed germination and plant growth" where they've been used raw, and advises against them anywhere you're growing from seed. Composted (at no more than 20% of a compost pile) or used as a thin, covered layer, they're a fine soil amendment; sprinkled straight onto a seed bed, they can do more harm than good.
Diseases
Pests
Cucumbers, Seed to Harvest
Plan your Cucumbers planting
When to sow and plant Cucumbers depends on your own frost dates. Check the UK vegetable planting calendar, or the month-by-month guides that cover Cucumbers: April, May, June. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Cucumber 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.
9 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
Do cucumbers come back every year?
No. Cucumbers are very tender and can be killed by light frosts (Clemson Cooperative Extension), so the plants don't come through winter: sow fresh seed each year.
Should I pinch off cucumber flowers?
It depends on the type. Greenhouse all-female varieties must not be pollinated, or the fruits may be bitter, so remove any male flowers (the ones without a tiny fruit behind them) that appear. Outdoor varieties produce both male and female flowers, and the females need pollinating to set fruit, so don't remove the male flowers (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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