When should I sow cucumber seeds in the UK?

Mid-April indoors for both greenhouse and outdoor types. Greenhouse plants go into the border or pots in late April–early May; outdoor plants go out after the last frost (mid-May south, early June north). Don't sow direct outside — cucumbers hate cold wet soil.

Greenhouse or outdoor cucumbers — what's the difference?

Greenhouse types (Carmen F1, Telegraph, Femspot): all-female F1 hybrids bred to fruit without pollination. No seeds, no bitterness, long smooth fruit. Need consistent warmth above 18°C; greenhouse / polytunnel / conservatory only. Outdoor / ridge types (Marketmore, Burpless Tasty Green): hardier; pollinated by bees; shorter spinier fruit; some seeds; can be slightly bitter if stressed. Tolerate UK outdoor conditions in southern England. Pick one type per growing area.

Why are my cucumbers bitter?

Inconsistent watering — the dominant cause. Cucumbers stressed by drought (even brief) produce cucurbitacin, the compound that makes them bitter. Water deeply 2–3 times a week; mulch heavily; never let the soil dry out. Other causes: cold weather (under 15°C), pollination of greenhouse all-female types by stray male flowers (remove any male flowers in greenhouse types), or simply a stressed plant.

Why are my cucumber leaves going yellow with white patches?

Powdery mildew (Podosphaera xanthii) — the most common late-season cucumber disease in UK greenhouses and outdoor crops. Worse in dry-after-wet weather. Remove the worst-affected leaves; improve airflow (ventilate the greenhouse, space plants further apart); water at the base only. A milk spray (1:9 milk:water) weekly helps. Resistant cultivars (Marketmore More 76, Vorgebirgstrauben) suffer less.

How do I prune indoor cucumbers?

Train the main stem up a vertical string. When the main stem reaches the top of the support, pinch out the growing tip. Side-shoots: pinch out at 2 leaves above the first developing cucumber to focus energy on fruit. Male flowers: remove any that appear on supposedly all-female F1 hybrids (they cause pollination and bitter seedy fruit). Tendrils can be left or removed for tidiness.

Can I grow cucumbers in containers in the UK?

Yes — bush varieties (Bush Champion, Picolino) and dwarf indoor types (Petita) in 30-litre containers work. Use rich peat-free compost; water daily in summer; feed weekly. Train climbing types up a tall stake or wigwam. Container plants need more attention to watering than ground plants — they dry out fast.

Gurke

Cucumis sativus

Sow cucumber seed indoors from mid-April; plant out after the last frost into a greenhouse or polytunnel border (or sheltered south-facing outdoor spot for ridge types). Cucumbers are frost-tender (RHS H1c) and split sharply by type: greenhouse / indoor cucumbers (Carmen, Telegraph, Femspot — all all-female F1 hybrids) want consistent warmth above 18°C and produce long smooth fruits; ridge / outdoor cucumbers (Marketmore, Burpless Tasty Green) tolerate UK summer outdoors in southern England, with shorter prickly fruits. Water consistently — drought makes cucumbers bitter. Feed weekly with high-potash from first flowers. Pick fruit young (15–20 cm) and often; leaving fruit on the plant shuts down further flowering. Powdery mildew is the main disease in late summer.

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