How to grow courgettes and the best varieties

Courgettes are a summer favourite that produce masses of fruit so you'll only need a couple of plants for most households.

How to grow courgettes: month by month

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Best courgette varieties

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Full testing results for courgettes

Green courgettes

Yellow courgettes

Novelty fruit

How we test courgettes

1. We grew 20 varieties of standard green, yellow, novelty or ball courgettes, selecting new or previously untested varieties to grow alongside previous Best Buys. 
2. We sowed the seeds in modular trays in a greenhouse in mid-May, and then planted out the best five plants of each variety in open ground. 
3. We waited until after the risk of frost had passed in mid-June to plant out. 
4. The ripe fruit was picked twice weekly in peak season, and we recorded the number and weight of those that were more than 15cm long. We also assessed the quality and characteristics of 10 representative fruit from each variety. 
5. We tasted the fruit, both raw and after being microwaved for three minutes, assessing each one for the strength and attractiveness of its flavour, as well as the succulence and texture of the skin, flesh and pulp.

When to sow

Courgettes are very sensitive to frost. Sow the seeds in late April or early May, no more than four weeks before it’s safe to plant outside in your area. Sow the large seeds individually into 7cm pots of a Best Buy compost for sowing seeds in a heated propagator or on a warm windowsill at about 20ºC. For most households, two plants will produce more than enough fruit.

Caring for your plants

Planting

Dig a hole about 30cm in depth and diameter. Fill it with a mixture of soil and garden compost or well-rotted manure, leaving a slight mound. Wait until the danger of frost has completely passed before you plant out in late May or early June. By this time, the young plants should have at least one large leaf.

Growing in containers

Some varieties are compact enough to grow in pots, such as 'Sure Thing' and 'Patio Star'. Use a container that has a volume of at least 10L and use a Best Buy compost for containers mixed with a Best Buy controlled-release fertiliser. Check if the compost feels dry to the touch every day and water thoroughly when needed. Feed plants in containers with a tomato food (high in potash) to encourage fruit.

Discover our Best Buy tomato feeds

Protecting from frost

Cover them with fleece until they are growing strongly.

Watering

In dry weather, water every 2 to 3 days with a decent amount. When it's hot, each plant can produce one or even two courgettes every day, when there is plenty of moisture around the roots.

How and when to harvest

Harvest in: July to September

Harvest the fruits when they reach 10-15cm long, or even smaller, to avoid a glut. If any fruit get missed and grow too large, cut them off to encourage the plant to produce more fruit.

Common growing problems

Powdery mildew

Powdery mildew usually appears in late summer or early autumn as the plants start to run out of steam. You will first see a white dusting on the leaves, which gradually becomes more severe, before the leaves turn yellow and die. 

Read more about powdery mildew.

Strange-coloured leaves

Several varieties of courgette, including ‘Royal Flush’, have smooth-surfaced silvery patches on their leaves. This is perfectly normal and does not require action.

Yellow-fruited varieties may also produce yellow leaves. This puts commercial producers off growing them, because they can look a bit sickly even though they’re perfectly healthy. Again, it’s nothing to worry about if you’re growing them.

Rotting fruits

The fruits start to develop normally and then, when still quite small, start to discolour and rot at the flower end. The rot then spreads back along the fruit towards the stem.

Read more about rotting courgettes.

No fruit

Sometimes courgettes fail to fruit much, especially during dry weather and when grown in pots.

Read more about courgettes failing to fruit.

Virus

Courgettes, squash and their relatives are prone to virus infections and symptoms include yellowing, poor growth, stunting and mosaicing, ring-spotting and streaking of the foliage, usually combined with a very poor or non-existent yield. 

Read more about virus.