How to Grow Courgettes

Courgettes are easy to grow and producing many fruits per plant which generally means that two plants will produce ample courgettes for most families.  Courgettes are not frost hardy, which means the plant should be protected from frost and not planted out until late May/ June when the risk of frosts has passed. Even then if it is cold, or a chilly wind, cover with a cloche until the weather picks up.

Courgettes can be grown in containers but note Courgettes grow into large plants  and need a fair amount of space between plants about 50/60cms (18-24".)  If Courgettes are grown in pots they will need very regular feeding and watering.  Whether growing Courgettes in the ground or pots, Courgettes like plenty of organic material and when fruiting the plants will benefit from regular feeding.

Growing Courgettes from seed

Courgettes produce a large seed, which is easy to handle, and to germinate provided they have enough warmth. Place one seed in a small pot, cover with thin layer of compost and spray lightly with water. To maintain the right atmosphere it is essential to cover either in propagator or with poly bag which needs to be secured with string or an elastic band to keep the plant firmly sealed in during the germination process.

Keep in a warm place until germination has taken place and then remove the bag or take out of the propagator. Do not be tempted to leave under cover in the warmth for too long as this can produce leggy seedlings. Keep frost free until ready for planting out.  

Watering Courgettes

A tip about watering small courgette plants, when they are small and before maturity. Take care not to over water them. Immature and small courgette plants are prone to rot at the stem neck, where it meets the soil, if the summer is cold or wet, or if the plant is over watered. This makes it important to avoid over watering, especially during the early stages of growth.

This is true also of cucumbers and squashes, of the same veg family. Avoid over watering in early stages.

The reverse is true once the plant is established when courgettes needs regular watering and if possible, to the roots not the leaves. One way of doing this is to sink a plastic bottle next to the plant when you plant it out, with the base cut out. This makes a funnel so that when you water into the bottle it goes direct to the roots.

 Once established growing courgettes appreciate a weekly feed, proprietary tomato food does well.

Common problems when growing courettes

As a Courgette plant matures the leaves often get white markings on them as in the image left. This is nothing to worry about and the plant is healthy, it is part of the courgette leaf's appearance.   

Cold weather: courgettes don't like it and will produce fewer fruits. This is because they need a lot of pollination and generally, when the weather is cool, there are less pollinators about.

This also occurs if there is a preponderance of male flowers.

Poor pollination and the mystery of male and female flowers

If the summer is poor courgette plants may respond with poor pollination. Courgette plants produce male and female flowers. The courgette flower which is female has a bump, or swelling at the base which is the immature embryo fruit. This is how you identify it as a female flower compared with the males stems which are straight with no bump. In the image the male stems are marked and straight, the females have a swelling, which becomes the courgette.

If the summer is poor you can help pollination. Pick a male flower, remove outside leaves and then brush the anther (middle bit of male flower) over the inside of the female flower (stigma) and it should pollinate. One male flower can pollinate several females. This makes it sound as if growing courgettes is difficult; it's not, and normally the problem is the glut of courgettes, which is why most gardeners only grow a couple of plants. Because courgettes like it warm they usually pick up later in the summer so if there are no fruits early in the summer there is no necessity to hand pollinate, you can just wait for the weather to improve. 

If you notice the fruits dropping off and rotting before coming to maturity, this is caused by a lack of pollination.

Good varieties of Courgette to grow are 'El Greco' usually prolific, mid-green fruits and good disease resistance. 'Supremo' is compact, so good for smaller gardens, or containers.  If you are looking for colour 'Parador' is a bright yellow variety and 'Defender' is a F1 green variety. All of these recommended varieties have the RHS award of garden merit.

Last updated 18.06.2020