How to Grow Courgettes

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.  

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, especially if the summer is cold or wet, or if the plant is over watered. It is 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 in full growth, courgettes need 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 directly to the roots.

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

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.

If the summer is poor, courgette plants may respond with poor pollination. Courgette plants produce male and female flowers.  A female courgette flower 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. These recommended varieties have the RHS award of garden merit in the 2021 trial.