Growing Courgettes Successfully in British Summers

Why courgettes earn their keep

Few crops repay a little attention quite so generously as the courgette. Give a single plant good soil, a sunny spot and a steady supply of water, and you will be harvesting firm, glossy fruits from mid-summer right through to the first cold nights of autumn. Two or three plants are plenty for a family; more than that and you will find yourself leaving bags on neighbours' doorsteps.

The flavour is the real reward. A courgette picked at ten centimetres and cooked within the hour is nutty, sweet and firm — nothing like the watery, tired specimens that sit in supermarket chillers for a week. They are also one of the most forgiving crops for a beginner, provided you respect two things: they hate cold, and they hate inconsistency.

Sowing indoors: timing matters

Courgettes are tender plants with no tolerance for frost, so in the UK they are always started indoors or under cover. Sow from late April to mid-May in most areas, and push it back a fortnight if you garden in the north or at altitude.

• Pots: use 7–9cm pots or modules, one seed per pot. Courgettes resent root disturbance, so sow where they can grow on for three or four weeks.
• Depth: push the seed in on its edge, about 2cm deep. This helps it shed the seed case cleanly.
• Temperature: germinate at 18–21°C. Seedlings usually appear in five to eight days.
• Light: move them to a bright windowsill or greenhouse the moment they break the surface, or they will stretch into pale, leggy plants that never quite recover.

If you have the space, make a second sowing in early June. It fills the gap when the first plants begin to tire and keeps the kitchen supplied into September.

Hardening off and the frost risk

This is the step most gardeners rush, and it costs them a fortnight of growth. Plants raised indoors have soft, thin leaves that scorch and sulk in direct sun and cold wind. Harden them off over seven to ten days: put them outside in a sheltered, shaded spot for a few hours on the first day, then gradually increase their time outdoors and their exposure to sun, bringing them in at night. Ease off watering slightly during this period to toughen them up.

Plant out only when the soil has reached around 12°C and night temperatures are reliably above 10°C. In southern England that is usually late May; in northern England and Scotland, early June. Keep a sheet of horticultural fleece to hand — a cold snap in early June can set plants back badly, and fleece thrown over them for two nights will save the crop.

Planting out and giving them room

Courgettes are hungry, thirsty plants and they sprawl further than the label suggests. Choose a sunny, sheltered spot and prepare it properly.

• Feed the soil first: fork in two or three buckets of well-rotted manure or garden compost per planting station.
• Space them out: allow 90cm between bush varieties and a metre between rows. Crowded plants are more prone to mildew and harder to water properly.
• Plant into a shallow hollow: a slight dip around the stem acts as a saucer and directs water straight to the roots rather than running off.
• Mulch: once the soil has warmed in early summer, spread a layer of compost or straw to hold moisture and keep fruit clean.
• Guard young plants: slugs and snails will demolish seedlings overnight. A ring of wool pellets, a copper collar or a night-time torch patrol all work.

Watering, feeding and steady growth

Consistency is the whole game with courgettes. The plant produces fruit at a remarkable rate, and it cannot do that from dry soil. Irregular watering — a week of neglect followed by a soaking — is the single most common cause of bitter fruit, misshapen fruits and blossom end rot, where the tip turns brown and leathery.

Water deeply at the base every day or two in hot weather, aiming for roughly five to ten litres per plant per week, and considerably more for plants in pots or grow bags. Morning watering is best; it keeps the foliage dry overnight and reduces mildew. Once the first flowers open, begin feeding weekly with a high-potash tomato feed to keep the fruits coming.

If fruits form but then shrivel and drop, pollination is the problem. Courgettes carry separate male and female flowers — the female has a tiny fruit behind the petals. If bees are scarce, pick a male flower, strip its petals and dab the pollen onto the centre of a female flower by hand. Do this mid-morning and the fruit will swell within days.

Harvesting well and keeping fruit sweet

Cut courgettes young, at 10–15cm, and check plants every couple of days in peak season. Leaving a fruit to swell into a marrow signals the plant to slow down, and you will lose a fortnight of production. Twist gently or cut with a sharp knife, and take the flowers too if you like — they are excellent stuffed and fried.

If a courgette tastes harshly bitter, do not eat it. Bitterness comes from cucurbitacin, a compound produced when plants are stressed by drought, cold or erratic watering, and in rare cases it can cause stomach upset. Keep watering evenly and the problem almost always disappears. Later in the season, powdery mildew may dust the leaves white; remove the worst affected foliage, water consistently, and the plants will usually keep cropping until the nights draw in.

From plot to plate: rustic home cooking

Fresh courgettes need very little done to them. Slice them lengthways, brush with olive oil and griddle until charred, then dress with lemon, good salt and torn mint. Grate them for fritters — salt first, leave in a colander for twenty minutes, then squeeze dry so the batter holds. Fold them into a lemon and courgette cake, or slow-cook them with aubergine, peppers and tomatoes for a proper ratatouille that tastes of late summer.

Any glut can be grated and frozen in bags for winter cakes, or sliced and dried for soups. That, really, is the quiet pleasure of growing your own: a plant that asks for sun, water and a bit of patience, and gives you a season's worth of cooking in return.