Bell Pepper
Capsicum annuum
Bell peppers need warmth and a long season to produce their sweet, crunchy fruits, making them ideal for greenhouse growing in the UK. Start seeds early — February or March — in a heated propagator at 18–21°C. Transplant into final positions (grow bags, large pots, or greenhouse borders) in May once temperatures are consistently warm. Outdoor growing is possible in sheltered, south-facing spots in southern England, but results are hit-and-miss. Green peppers are simply unripe red, yellow, or orange peppers — leaving them on the plant longer gives you coloured fruits with sweeter flavour, but reduces overall yield. Pinch out the growing tip when plants reach 30cm to encourage bushier growth. Water consistently and feed weekly with tomato fertiliser once the first fruits set. 'California Wonder' is the classic variety; 'Gypsy' F1 is earlier-ripening and more reliable outdoors.
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When to Sow Bell Pepper
Sow bell pepper in February, March, April.
Time to Harvest Bell Pepper
Expect to harvest approximately 5 months after sowing.
Companion Plants
Expected Yield
5–10 peppers per plant; more green, fewer if waiting for them to colour.
Common Problems with Bell Pepper
Slow growth
Bell peppers are heat-loving plants that barely grow in temperatures below 15°C. In most of the UK, they perform far better under cover in a greenhouse, polytunnel, or even a sunny conservatory than outdoors. Start seeds early (February–March) in a heated propagator, and maintain consistent warmth throughout the season to keep growth steady.
Blossom drop
Flower buds fall off without setting fruit, usually triggered by cold night temperatures (below 12°C), dramatic temperature swings, or irregular watering. Keep plants in a sheltered, warm position and water consistently — the stress of drying out and then being soaked causes the plant to shed flowers it can't support. Maintaining even temperatures under cover significantly reduces this problem.
Aphids
Green or black aphids cluster on young shoot tips and flower buds, curling leaves and weakening the plant. Introduce the biological control Aphidius colemani or the predatory midge Aphidoletes in greenhouses. Outdoors, blast off with a strong jet of water or spray with diluted washing-up liquid. Avoid crushing them on the plant, as this can spread viruses.
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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.