How to Grow Courgettes on an Allotment: UK Growing Guide

Courgettes are one of the most rewarding crops you can grow on a UK allotment. A single healthy plant can produce 20–30 fruits over a summer — sometimes faster than you can eat them. They're forgiving for beginners, respond well to good watering and feeding, and the plants themselves are impressively vigorous. Here's everything you need to know to grow excellent courgettes.

Best Courgette Varieties for UK Allotments

• Defender F1 — the most popular UK allotment courgette; very reliable, resistant to cucumber mosaic virus

• Astia — excellent compact variety ideal for containers; very productive

• Black Forest — climbing courgette; saves space by growing upward rather than sprawling

• Tromboncino — climbing Italian heirloom with superb flavour; needs strong support

• Romanesco — Italian heritage variety with ridged fruits and nutty flavour, excellent for eating whole when small

When to Sow Courgettes in the UK

Courgettes are frost-tender — sow too early and they'll outgrow their pots before it's safe to plant out. The ideal timing is to sow indoors in April (late April in the north) for planting out late May–June after the last frost. Outdoor direct sowing is possible from late May–June once soil has warmed.

How to Sow Courgettes from Seed

Sow one seed per 7–9cm pot on its side — this reduces the risk of the seed rotting at the pointed end. Cover with 1cm of compost and place on a warm windowsill or in a propagator at 18–20°C. Seeds germinate in 3–7 days in warm conditions. Move to good light as soon as the seed leaf appears to prevent legginess.

Planting Out Courgettes

Courgettes need more space than most beginners expect: 75–90cm between plants, in all directions. They sprawl dramatically and crowding leads to poor airflow, more disease, and reduced yields. Dig a generous hole, add compost or well-rotted manure, and plant at the same depth as the pot. Water in well.

Watering and Feeding Courgettes

Courgettes are thirsty plants and inconsistent watering causes problems — poor fruit set, bitter fruits, and flower drop. Water deeply at the base of the plant every 2–3 days in dry weather. Mulching around the plant conserves moisture and is highly recommended. Once flowering starts, feed weekly with a liquid tomato feed or comfrey liquid.

Why Won't My Courgettes Fruit? Pollination Problems

This is the most common courgette problem. Courgette plants produce separate male flowers (on long thin stems) and female flowers (with a tiny courgette behind the petals). In the early season there are often only male flowers, or cold and wet weather reduces pollinator activity. If fruits are starting to form then shrivelling at the tip, lack of pollination is almost always the cause.

To hand-pollinate: pick a male flower, remove the petals, and gently rub the pollen-covered centre against the centre of a female flower. Do this in the morning when flowers are fully open. You can see if it's worked — a successfully pollinated courgette will swell rapidly within days.

Harvesting Courgettes for Maximum Yield

Harvest courgettes at 10–20cm long — the sweet spot for flavour and texture. Never leave them to grow into marrows: a courgette left unpicked signals the plant to stop producing, and within a week you'll have a giant marrow and no new fruits. Check plants every 2–3 days during the main season. Use a sharp knife — pulling or twisting damages the plant.

Common Courgette Problems

• Powdery mildew (white coating on leaves) — very common in late summer. Keep soil moist, improve airflow, remove badly affected leaves. The plant will usually keep producing despite mildew.

• Slug damage to young plants — protect with barriers, go out at night, or use ferric phosphate pellets.

• Rotting at the base of fruits — usually a combination of poor pollination and wet weather. Improve drainage and hand-pollinate.

• Bitter courgettes — caused by drought stress. Water more consistently and mulch around plants.

How Many Courgette Plants Do I Need?

One or two plants is almost always enough for a household. Three plants in full production will provide more courgettes than most families can possibly eat. If you find yourself with a glut (and you will), courgettes freeze well when sliced and blanched, make excellent soup, and even work in cakes. Share with neighbours.