Cucumber (Cucumis sativus)
6 sources cited · Verified
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
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.
Cucumbers (Cucumis sativus) — Tender warm-season annual.
This is a frost-tender crop — it will not survive below about 6°C — so in UK conditions the growing year is built around starting it under cover and moving it out only once the risk has passed.
Core growing advice on this page is checked against named horticultural and university-extension sources — see References.
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.
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).
Soil & Growing Conditions
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 6 - 6.5 |
| Sunlight | 6-6 hours direct sun |
| Germination temp | 21C |
| Optimal growing temp | 18-32C |
| Minimum survivable temp | 6C |
| Time to harvest | 50-70 days |
| Drainage | RHS: a "warm sunny site outdoors" and a "warm, sunny, sheltered spot". Neither source states a soil texture requirement. |
| Lifecycle | Tender warm-season annual. Frost-tender at every stage: sown under cover in warmth, grown on and cropped within a single season, and killed by the first autumn frost. It is never overwintered. |
| Edible parts | fruits |
At a Glance
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 21C (70F) 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 12C (53F) 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 18-25C 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 7-10C) and humid for around a week. |
Harvest & Storage
Diseases
Pests
Cucumbers, Seed to Harvest
References
-
Tier 1. Primary UK source: greenhouse vs outdoor (ridge) types; sow 1-2cm deep on side at 21C; plant out from late May (greenhouse) / early June outdoors once >12C, 30cm apart; training and pinching out; removing male flowers on all-female types; watering/feeding; harvest sizes and cutting; powdery mildew, red spider mite, whitefly, slugs and snails.
-
Tier 1. US extension corroboration: warm-season crop, uniform moisture to 6in depth, storage at 45-50F and 95% humidity for about a week, typical days to harvest.
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Tier 1. US extension source for spacing, uniform moisture supply during fruiting, and avoiding bitter/misshapen fruit.
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Tier 1. Host-specific: CMV has a very wide host range and no cure; stunts and distorts plants and deforms fruit; infected plants should be removed.
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Tier 1. UK climate context for the south-to-north spring gradient used to derive regional plant-out windows for this frost-tender crop.
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Tier 1. International agronomic ranges (temperature, pH).
6 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
When should I plant cucumbers out in the UK?
In southern England, from late May. In northern England and Scotland, wait until early June. Treat these as a guide rather than a fixed date — the governing rule is to plant out only once frost risk has passed and temperatures are reliably warm enough.
When do I sow cucumbers?
Sow early February to late April, at around 21°C for germination.
How long do cucumbers take to grow?
Typically 50–70 days, depending on cultivar and growing conditions.
What soil pH do cucumbers need?
A pH of about 6–6.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect cucumbers?
Our data links 2 diseases and 4 pests to this crop. See the sections above for each one and how to manage it.
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.
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Tools That Help With This Crop
Use these links when the guide moves from reading into sowing, planting, watering, and keeping the crop healthy.
Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.