Cucumber
Cucumis sativus
Cucumbers come in two types for UK growers: greenhouse (smooth-skinned, longer) and outdoor/ridge (shorter, sometimes spiny). Outdoor varieties like 'Marketmore' and 'Crystal Lemon' are tough enough for UK summers and produce heavily from July to September. Greenhouse varieties give earlier, more prolific crops but need consistent warmth and humidity. All cucumbers are tender — don't plant out until early June in most of the UK. They love to climb, and training them up strings or trellis saves space and keeps fruits clean and straight. Water consistently; erratic watering causes bitter-tasting fruits. Feed weekly with tomato fertiliser once fruits start forming. For greenhouse types, remove male flowers to prevent pollination, which makes fruits bitter and seedy. Outdoor types need pollination, so leave the bees to do their work.
Plan where to grow Cucumber using our vegetable garden planner.
When to Sow Cucumber
Sow cucumber in April, May, June.
Time to Harvest Cucumber
Expect to harvest approximately 3 months after sowing.
Companion Plants
Expected Yield
Outdoor plants give 10–20 fruits; greenhouse plants can give 20–50.
Growing Tips
Can be grown vertically to save space
Common Problems with Cucumber
Powdery mildew
A white powdery coating on leaves that's almost inevitable by late summer. Keep plants consistently watered (dry roots make the plant more susceptible), ensure good ventilation in greenhouses, and remove the worst-affected older leaves to slow the spread. Resistant varieties and regular feeding help plants outgrow the damage.
Bitter fruit
Bitter-tasting cucumbers are caused by a compound called cucurbitacin, which builds up when plants are stressed by irregular watering, wide temperature swings, or dry conditions. Water deeply and consistently, maintain even temperatures under cover, and remove male flowers on greenhouse varieties to prevent pollination, which also causes bitterness and seedy fruit.
Whitefly
Tiny white flies cluster on leaf undersides, sucking sap and excreting sticky honeydew that attracts sooty mould. Hang yellow sticky traps at plant height to monitor and reduce numbers. For biological control, introduce the parasitic wasp Encarsia formosa — it's highly effective under cover. Good ventilation and avoiding overcrowded planting reduce the humidity whitefly thrives in.
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Cherry Tomato
Solanum lycopersicum var. cerasiforme
Cherry tomatoes are one of the most rewarding crops for UK allotment growers. These small, sweet fruits ripen reliably even in cooler summers, producing heavy trusses from July right through to October. They thrive in grow bags, pots, or directly in the ground, making them versatile for any plot size. Pinch out side shoots regularly on cordon varieties to channel energy into fruit production. Bush varieties like 'Tumbling Tom' need no training and work brilliantly in hanging baskets. Feed weekly with a high-potash tomato feed once the first fruits set. The key to great flavour is letting them ripen fully on the vine rather than picking early.
Beefsteak Tomato
Solanum lycopersicum
Beefsteak tomatoes produce the large, meaty fruits that are perfect for slicing into sandwiches and burgers. They need a long growing season in the UK, so starting seeds early under cover is essential. These are almost always grown as cordons — train them up a single stem, removing side shoots weekly. Each truss produces fewer but much larger fruits than cherry types, often weighing 200–500g each. They benefit from greenhouse growing in cooler regions, though sheltered outdoor spots in the south can produce good results. Consistent watering is critical; irregular watering causes blossom end rot and fruit splitting. Stop the plant at 4–5 trusses to ensure fruits ripen before autumn.
Nantes Carrot
Daucus carota
Nantes carrots are the gold standard for flavour — sweet, crisp, and cylindrical with a smooth skin that barely needs peeling. They perform well in most UK soils but prefer light, stone-free ground to grow straight. If your soil is heavy clay, grow them in raised beds or deep containers filled with sandy compost. Sow thinly to avoid the need for heavy thinning, which attracts carrot fly. Cover rows with fine mesh or enviromesh as a physical barrier against carrot fly — this is far more reliable than companion planting alone. Successional sowing from March to July gives you carrots from June through to winter. Late sowings can be left in the ground over winter under a thick mulch of straw.
Butterhead Lettuce
Lactuca sativa
Butterhead lettuce produces soft, rounded heads with tender, buttery-textured leaves that melt in the mouth. It's one of the quickest salad crops to grow — ready in as little as 8 weeks from sowing. Unlike iceberg types, butterheads tolerate partial shade and are less likely to bolt in warm spells. Sow small batches every 2–3 weeks from March to September for a continuous supply. They work well as an intercrop between slower-growing vegetables like brassicas and leeks. Water consistently but avoid wetting the leaves to reduce the risk of grey mould. 'All the Year Round' is the classic UK variety and lives up to its name, performing well in almost every season.