Growing Courgettes in the UK: A Beginner's Guide

If you grow one vegetable this year, make it courgettes. They germinate in days, romp away through summer and reward the smallest amount of care with an almost comic abundance of fruit. Two or three plants will keep a household in courgettes from July until the first frosts, with plenty spare for the neighbours. They are the classic starter crop for anyone building towards a bit of self-sufficiency, and a cheerful gateway into growing your own veg.

Why are courgettes such a good crop for beginners?

Courgettes forgive a lot. They grow quickly, they are not fussy about variety, and they produce so heavily that even a mistake or two rarely costs you the harvest. Sow a seed in late April and you can be cutting your first fruit by early July.

The famous downside is also their greatest charm: they are wildly over-productive. Leave a courgette plant unpicked for a few days in August and you will come back to a marrow the size of your forearm. This is the classic courgette glut, and every UK grower runs into it. It is a lovely problem to have, and we will come to what you can do with the surplus later on.

Two or three plants will keep a household in courgettes all summer, with plenty spare for the neighbours.

When and how do you sow courgettes in the UK?

You have two easy options, and many growers do both to spread the harvest.

The reliable route is to start them off indoors on a warm windowsill or in a greenhouse. From mid-April to mid-May, sow one seed per small pot of multipurpose compost, about 1.5cm deep. Sowing the seeds on their side helps stop them rotting. They germinate fast, usually within a week, and grow into sturdy young plants ready to go outside once the weather warms.

The other option is to direct-sow outdoors from late May into June, once the soil has warmed and the frost risk has passed. This is simpler but gives you a slightly later crop.

1. 1

   Sow indoors

   From mid-April to mid-May, sow one seed on its side, 1.5cm deep, in a small pot of compost. Keep on a warm windowsill and expect germination within a week.

2. 2

   Grow on

   Water sparingly and let the young plants develop a couple of true leaves. Pot on if roots fill the pot before it is warm enough to plant out.

3. 3

   Harden off

   For 7 to 10 days before planting out, stand plants outside by day and bring them in at night so they adjust to outdoor conditions.

4. 4

   Plant out

   After the last frost (late May to early June), plant into rich soil in full sun, 90cm apart, and water in well.

5. 5

   Feed and water

   Water regularly at the base. Once the first fruits swell, feed every 10 to 14 days with a high-potash tomato feed.

6. 6

   Harvest young

   Pick fruit at 10 to 12.5cm, every day or two. The more you pick, the longer and heavier the plant crops.

Where do courgettes grow best?

Courgettes are hungry, thirsty plants, and they reward good preparation. Choose a sunny, sheltered spot and dig in plenty of well-rotted manure or garden compost before planting. If you are building up your own supply, this is exactly the kind of job homemade compost is made for: rich, moisture-retentive soil is what keeps a courgette cropping.

They also grow happily in large containers or growbags, which makes them a good choice for a patio or small garden. Use a pot at least 45cm wide filled with good compost. The one catch is that containers dry out fast, so pot-grown plants need more frequent watering and feeding than those in the ground.

Because the plants get big and sprawling, give each one at least 90cm (3ft) of space in every direction. It looks like far too much room when you set out a small plant in June, but by August you will be glad of it. Generous spacing also keeps air moving around the leaves, which helps hold off mildew later in the season.

How much watering and feeding do courgettes need?

Plenty of both. Water regularly and deeply, aiming to keep the soil consistently moist, and step it up in dry spells and once the plants are fruiting. Container plants in particular may need watering daily in hot weather.

Water at the base of the plant, around the roots, rather than over the leaves. Wet foliage encourages powdery mildew, which is the main problem courgettes face later in summer, so keeping the leaves dry is a simple bit of prevention.

Plants in rich ground often crop well without extra feeding, but a boost pays off, especially in containers. Once the first fruits start to swell, feed every 10 to 14 days with a high-potash tomato feed. The extra potassium encourages flowers and fruit rather than lush leaf, which is exactly what you want.

When and how should you harvest courgettes?

This is the single most important thing to get right, and it is where beginners most often go wrong. Pick your courgettes young, at around 10 to 12.5cm (4 to 5in) long, when they are tender and full of flavour. And pick often: every day or two at the height of summer.

Frequent picking is not just about quality. The more you harvest, the more the plant produces, because removing fruit keeps it flowering and setting new courgettes. Leave a fruit on the plant and it keeps swelling into a marrow, and once it does, the plant reads that as a signal to slow down and set far fewer new fruit. One overlooked courgette can noticeably reduce your harvest, so check the plants thoroughly, looking under the big leaves where fruit hides.

What are the common courgette problems, and how do you fix them?

Three issues account for most courgette troubles in the UK.

Powdery mildew. A white, dusty coating appears on the leaves, usually from late summer as nights cool. It is very common and rarely fatal, but it weakens the plant. Prevent it with good spacing, watering at the base, and keeping plants well fed. At the first sign, remove and destroy the worst-affected leaves to slow the spread.

Poor fruit set and rotting fruitlets. In cold, wet weather early in the season, baby courgettes often turn yellow and rot at the tip instead of swelling. This is usually down to a lack of pollination, because bees are less active in poor weather. The fix is to hand-pollinate: on a dry morning, pick a male flower (the one on a thin stalk, with no tiny fruit behind it), peel back its petals and brush its pollen gently into the open female flowers (each has a baby courgette behind it). One male flower carries enough pollen for three or four females.

Slugs and snails. Young plants are vulnerable when first planted out and can be stripped overnight. Protect them in the early weeks with your preferred slug control until they are large and tough enough to shrug off the damage.

What do you do with a courgette glut?

Sooner or later, every courgette grower has more than they can eat. When the kitchen bowl is overflowing and you have already given some to everyone you know, turn to preserving. Courgettes are excellent in a spiced chutney, and grating and freezing them keeps a supply for soups, cakes and fritters through winter. A late-season marrow or two is perfect for stuffing and roasting.

That endless summer supply is the whole point. A few plants, a bit of water and regular picking, and you have one of the most generous crops a UK garden can give you. Once you are hooked, take a look at the rest of the vegetables in the grow section for what to sow alongside them.