Cucumbers thrive in the warmth of a UK polytunnel or greenhouse, and with the right variety can even succeed outdoors in a sheltered, sunny spot during a good summer.
Founder & Head Grower, SoilCommander · RHS Level 2 · 12+ years growing in Yorkshire
I’ve been growing vegetables on my Yorkshire allotment and raised beds since 2012. Everything I write is based on what I’ve actually grown, failed at, and eventually got right in a real UK climate.
When to Sow Cucumbers in the UK
Sow cucumbers indoors from April to May, maintaining a temperature of at least 20°C for germination. Do not sow too early — cucumbers grow fast and become pot-bound quickly. The RHS recommends planting out into a heated greenhouse or polytunnel from late April, or into an unheated structure from late May.
Greenhouse vs Outdoor Varieties
There are two distinct types: greenhouse cucumbers produce long, smooth fruits and need indoor warmth throughout the season; ridge (outdoor) cucumbers produce shorter, rougher-skinned fruits and can grow outside in a sheltered, sunny position in the south from early June. Do not grow greenhouse varieties outdoors — they need warmth and dislike outdoor conditions.
Passandra F1
Mini cucumbers, all-female variety (no bitterness from male flowers). Prolific and reliable. Ideal for small greenhouses.
Flamingo F1
Standard length greenhouse cucumber. All-female, disease-resistant, very productive.
Marketmore
The most reliable outdoor cucumber for UK conditions. Dark green, slightly ridged fruits. Good flavour and disease resistance.
Crystal Lemon
Round, pale yellow fruits. Novelty variety with good outdoor performance. Sweet, non-bitter flavour.
Growing and Training
Plant into large containers or greenhouse borders filled with rich compost. Train the main stem up a vertical support. Pinch out the growing tip once it reaches the top of the support. For greenhouse varieties, remove all male flowers (those without a tiny fruit behind the flower) to prevent bitter fruits. Side shoots: pinch out two leaves beyond each fruit on greenhouse types.
Watering and Feeding
Cucumbers need consistent moisture — irregular watering causes bitter fruits and blossom drop. Water daily in hot weather. Begin weekly high-potash liquid feed once fruits start to form. Mulch around plants to retain moisture.
Harvesting
Harvest greenhouse cucumbers when 15–25cm long. Ridge cucumbers at 15–20cm. Pick regularly — leaving overripe fruits on the plant signals it to stop producing. Cucumbers are best eaten fresh; they store for only 2–3 days in the fridge.
Plan Your Full Season
The SoilCommander UK Vegetable Garden Planner covers greenhouse and outdoor crops with monthly sowing and care guides.
Get the UK Garden Planner →Can cucumbers grow outdoors in the UK?
Yes, ridge (outdoor) varieties like Marketmore can succeed outdoors in a warm, sheltered, south-facing position in southern England. In the north, a polytunnel gives much more reliable results.
Why are my cucumbers bitter?
Bitterness is usually caused by temperature stress, drought, or male flowers pollinating greenhouse types. Use all-female greenhouse varieties, remove any male flowers that appear, and keep temperatures and watering consistent.
How often should I water cucumbers?
Daily in warm weather — cucumbers are thirsty plants. Irregular watering is a major cause of poor fruiting and bitterness. A deep soak every day in summer is better than frequent shallow watering.
Browse sowing dates for all crops in the UK vegetable planting calendar or explore all UK vegetable growing guides.
Tools That Help With This Crop
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Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.