Courgette: from the first flowers to a summer of harvests

Choose by flavour, shape and use

Ola Redonda: Round, light green courgettes with white speckles on a bushy plant: just the shape for small stuffed balls. Cut off a lid, hollow out the young fruit and fill with rice or vegetables. Include the scooped-out flesh in the filling.

No separate aroma is described. Harvesting young gives a tender courgette texture; the round shape is the clear cultivar difference here.

Black Beauty: The practical classic courgette: a non-vining plant for a regular summer harvest of young fruits. Cut young fruits lengthways for the barbecue or turn the harvest into soup. This gives both small and slightly larger specimens a place in the same kitchen.

The source advice centres on harvesting young for a tender texture. No specific sweetness relative to other green cultivars is documented.

Caserta: Light green, medium-length fruits with dark stripes make Caserta a fresh variation on uniformly green courgettes. Cut striped slices for a vegetable traybake or firm cubes for a quick stir-fry.

The firm flesh is described as good cooking quality. A separate claim about aroma or sweetness is absent; texture is the main distinction.

Cocozelle de Tripolis: Long, slender green courgettes with pale stripes; the classic elongated shape gains a visible pattern here. Cut fine, long slices for grilling or thin rounds for a summer vegetable dish.

The described flavour is mild. That mildness suits simple preparations in which the courgette remains recognisable.

Why grow your own courgettes?

You do not need a large vegetable bed to start with courgettes. One plant is already a good beginning: you see it change from a seedling into a broad plant with flowers and fruits. Looking beneath the leaves regularly during summer reveals exactly when there is something to pick.

Young fruits are versatile in the kitchen. Fry them briefly, grill slices or turn a generous harvest into soup. The flowers are edible too. Prefer male flowers for cooking and leave enough on the plant for pollination.

Sowing: start in April or May

For the Netherlands and Flanders, April to May is a practical period for starting indoors. This is guidance: work backwards from when you can plant out after the last night frost. Sowing too early produces large plants that still need to stay indoors for a long time.

Sow one seed per pot in moist seed compost, about 1–1.5 cm deep and on its side. Keep the pots warm, around 18–21 °C. After emergence, remove any lid and give the seedling plenty of light. Keep the compost moist without leaving the pot constantly wet.

Raising plants and acclimatising them gently

Courgettes grow quickly. Check that the pot still provides enough space and, if necessary, move the plant with its whole rootball into a larger pot. Pricking out from a shared tray is unnecessary if you sowed individually. Work carefully: damaged roots delay the start.

Before planting out, gradually acclimatise the plant to outdoor air, wind and sun. Start on a mild day in a sheltered spot and increase time outdoors. Bring it back inside on cold nights. A plant that has grown large indoors cannot immediately cope with everything outdoors.

Plant out once the cold has passed

Plant outdoors when the risk of night frost has passed and the soil has warmed. This is often from the second half of May or early June; your local forecast takes priority over the calendar. From late May or June, you can also sow directly outdoors.

Give the plant a sunny, sheltered spot. For an ordinary courgette, allow roughly 90 cm between plants or about one square metre. Some cultivars need more space. Set the rootball carefully in the planting hole and water to bring roots into contact with the soil.

A fertile bed, including on clay

Courgettes like soil that both retains moisture and lets excess water drain away. Mature compost helps prepare the bed. Do not put fresh manure close to young roots. Determine extra feeding from your soil and the product instructions; more is not automatically better.

On heavy clay, first look at where water remains after rain. Do not choose a low planting hole where the rootball stays wet. A well-drained bed, raised if necessary, gives a better starting point. Do not work wet clay into a smooth, smeared planting position.

Water and feeding: look at the soil first

Check the soil by the roots before watering. Water the soil so the root zone becomes properly moist; avoid a small daily splash that only reaches the surface. A pot dries out faster than a garden bed and needs more frequent checks in warm weather.

Mulch can help retain moisture once the soil is warm. Leave a little space around the stem. During fruit formation, give supplementary feed if necessary according to the packet. Record watering and feeding in My garden so you can see later what you actually did.

Recognising and pollinating flowers

A male flower stands on a thin stalk. Behind a female flower is already a small immature fruit: a miniature courgette. That little ball or cylinder is not yet a successful harvest. Pollen from a male flower must reach the female flower.

Bees and other insects help with this. In a closed greenhouse, reaching the flowers is difficult for them. Open the greenhouse in suitable weather; with few pollinators, you can gently transfer pollen from a fresh male flower to the female flower. Do this while the flowers are open.

Should you prune or train courgettes?

Most bush forms can simply be left to grow. Remove only badly damaged or diseased leaves when necessary. Leave healthy leaves in place: they help the plant grow. A climbing frame is not a fixed requirement for every courgette.

Costata Romanesco can spread more than a compact bush form. Choose the cultivar first, then reserve the space. A growth habit that fits easily in a large bed is not automatically a good choice for a small balcony pot.

If you want to grow upwards, place sturdy support beside the plant early and gently guide the main stem up. Tie loosely with soft material and check the loops during growth. A figure-of-eight tie separates stem and stake. The hollow stem is vulnerable: do not force an older plant or tie to a thin leaf stalk.

A supported bush courgette still grows differently from a true climbing cultivar and retains broad leaves. For standard courgettes, the RHS mentions a single sturdy stake about 1.8 metres long. Choose the growth habit deliberately and follow your own cultivar's spacing guidance. The growing illustrations above show how a garden bed, support and a large pot each need a different approach.

Harvesting: better young than impressively large

Usually pick elongated courgettes at about 15–20 cm, or smaller if preferred. For round cultivars, look at diameter; follow the cultivar description. Cut through the stalk with a clean knife or secateurs. Do not pull the fruit off the plant.

In good growing weather, look beneath the leaves every few days. A forgotten fruit can grow large quickly, with harder skin and coarser seeds. Regularly harvesting young fruits helps the plant continue producing.

Storing and using

Handle the harvest carefully: young skin damages easily. Preferably use courgettes within a few days and keep them cool. Before use, check for soft, rotting patches.

Have more than you can use straight away? Turn it into a dish you can freeze, such as soup or a vegetable stew. Before cooking, cut open an obviously oversized fruit and examine its skin and seeds. A large courgette has a different texture from the young harvest this variety is grown for.

What if the harvest disappoints?

Only flowers? The first are often male. Wait for female flowers to appear too. A small fruit turning yellow and dropping may indicate incomplete pollination, for example in cold weather or with few insects. Look at flowers and weather first, before adding fertiliser.

White, powdery patches on older leaves may be powdery mildew. Give plants air and avoid water stress. Yellow leaves have several possible causes: consider wet soil, drought and growth stage. A limp plant on a hot afternoon is no reason to water an already saturated bed again.

Saving your own seed? Start with reliable seed

Courgettes can cross with one another and with other forms of Cucurbita pepo. Seed from your own fruit therefore does not automatically reproduce the same cultivar. With F1 cultivars such as Eight Ball and Zephyr, offspring may differ even without such a cross. Choose reliable seed again for a predictable next crop.

Do not eat an unusually bitter courgette. Spit out a bitter mouthful and discard the fruit. Do not feed it to pets either. This is particularly a reason to be careful with unknown or home-saved courgette seed.