Growing courgettes in the garden

Courgettes are highly productive veg plants and are a must for every kitchen garden. Find out how to grow your own courgettes successfully in veggie patches and in pots.

Courgettes (Cucurbita pepo) are easy to grow, beginner-friendly plants that produce abundant crops. Growing courgettes in your garden or on your terrace or balcony is so rewarding – in the height of the growing season you can harvest three or four tasty courgettes a week! Keep reading to learn everything about growing and planting courgette seedlings.

Courgettes: origin and properties

The courgette plant is a summer squash in the cucurbit family (Cucurbitaceae), which can be recognised by its typical orange-yellow flowers and later by its fruits. Courgettes were first cultivated in Italy in the late 19^th century from squashes that originated in Central America. They are annual plants that are extremely sensitive to frost. Courgette varieties are divided into two groups: climbing courgettes or bush courgettes.

How to grow courgettes

Courgettes are usually first sown indoors or in a greenhouse and transplanted outside from mid-May onwards. Starting courgettes indoors shortens the time until the first harvest – the first fruits form as early as June. Here are our tips on how to successfully sow, prick out and transplant courgettes.

Sowing courgettes

Sow the courgette seeds in small pots or seed trays from mid-April. Use nutrient-poor soil for this, such as our Plantura Organic Herb & Seedling Compost, as the seeds have their own supply of nutrients. Sow 2 to 3 cm deep at a temperature of 18 to 20°C to ensure germination. Keep the soil moist for the next few weeks. After 7 to 10 days the first courgette seedlings will appear. Alternatively, sow your courgette seeds directly outdoors from mid-May, as soon as no more late frosts are expected. Direct-sown courgettes bear their first fruits after about 8 weeks.

Pricking out courgettes

Prick out and transfer seedlings to more nutrient-rich soil as soon as they grow their first courgette leaves (after their initial oval-shaped baby leaves). Fill 9 cm pots about halfway with a high-quality potting soil, such as our Plantura Organic Tomato & Vegetable Compost. It contains essential nutrients such as nitrogen, phosphorus and potassium, which will nourish your courgette seedlings until they are planted outdoors. When pricking out the courgette plants, use a widger, spoon or wooden ice lolly stick to pluck the seedlings, roots and all, out of the soil. Handle the courgette plant by the leaf to avoid damaging and bruising the stem and roots. Now place the courgettes in the half-full pots, fill up to the brim with potting soil and water well. Over the next few weeks, water the plants regularly and place them in a warm and sunny spot.

Planting courgettes outside

Transplant courgettes outdoors from mid-May, after the last frost. Space the courgette plants one square metre apart, so that each has about one metre of space on all sides. For narrower, climbing courgette varieties that are tied up on a trellis, space the plants 60 to 80 cm apart. The plants need plenty of space to spread out and to prevent fungal infections. Work some compost into the soil before planting because courgette plants are heavy feeders and need lots of nutrients. Plant the courgette seedlings in the soil just to below the leaf base. Be careful not to damage the stem of the plant. Then water vigorously and apply a mulch layer of lawn clippings around the plants. This is an effective care step – it helps the soil retain moisture and provides food for soil organisms. Find more useful tips in our article on courgette care.

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The right location for growing courgettes

On the whole, courgette plants are not very demanding when it comes to their location. The optimal location for courgettes is in well-drained, moderately-heavy, humus and nutrient rich soil with good water retention. The high-yielding vegetable loves warm, sunny and sheltered spots. To grow courgettes on a balcony, it needs to be south facing. Climbing courgette varieties can be trained to trail along balconies using a climbing aid. Courgettes can also be planted in raised beds. Here you should choose a space-saving, climbing courgette variety and plant it at the edge so it can grow down over the side of the raised bed.

Tips for choosing a good location for courgettes:

• Nutrient-rich, well-drained soil or potting compost
• Warm, sunny and sheltered
• Sufficient space between plants: 1-1.5m² per plant
• Growing courgettes on balconies and raised beds: Choose a climbing, space-saving variety and plant them facing south

Companion planting is beneficial for courgettes as they benefit from the nutrients supplied by other vegetable plants and vice versa. Here are the best companion plants for courgettes.

Growing courgettes in pots

In addition to outdoor cultivation, courgettes can also be planted in pots and placed in a warm, sunny location. Use a pot with a volume of at least 40 litres. Fill the pot with a nutrient-rich soil and then place the courgette seedlings in the pot. Water the courgettes regularly, as the soil in pots is at risk of drying out much more quickly. Give the courgettes in pots a protective layer of mulch.

How to propagate courgettes

With the right know-how, you can save your own courgette seeds to propagate the plants again next season. This only works with heirloom courgette varieties, not with plants from hybrid seeds. Cucurbits such as courgettes, squashes and pumpkins are strict cross-pollinators that depend on visits from insects. Cross-pollination by bees can be pretty much ruled out unless there is another closely related cucurbit plant within a radius of three kilometres. The plants produce purely male flowers with a long flower stalk and pollen and purely female flowers with a clearly visible ovary and sticky stigma. These flowers open for just one day at a time. To propagate heirloom variety courgettes and to prevent other varieties or even closely related squashes from crossing with them, it is best to pollinate the flowers by hand.

To pollinate courgettes by hand, you need about 6 to 12 healthy plants of the same variety that flower at the same time. For each female flower, you will need about three male flowers from another plant for successful pollination without inbreeding. Carefully close thickly swollen flower buds shortly before they open using masking tape in the evening hours. The next morning, pick the prepared male courgette flowers and remove the petals. This will expose the columnar anthers with pollen. Then carefully remove the tape from the female flower so that it unfolds. Then dab the stigma of the female flower with the pollen of the male flowers and then close the female courgette flower again with masking tape.

In the next few days, after successful pollination, the petals will die back to reveal a small fruit. Mark the courgette fruit so that you still know later which flower was the hand-pollinated one. Leave the fruit on the plant until the seeds are ripe. It will grow large and become hard on the surface until the stalk also dries out and the seeds are ripened. Harvest this courgette in late autumn before the first frost. Carefully cut it open and remove the seeds. Dry at room temperature and then store in a cool, dry and dark place for up to six years.

Summary propagating courgette seeds:

• Plant several plants of the same heirloom variety.
• Seal one female and three male buds of different plants the evening before the flowers open.
• The next morning, pick the male flowers and expose the stamens.
• Open the female flower and pollinate by hand with pollen.
• Re-seal the flower and mark the emerging fruit.
• Leave courgettes on the plant until seeds are ripe, harvest before frost.
• Cut open fruit, remove seeds and allow to dry out.
• Store courgette seeds in a cool, dry and dark place.

The courgette’s harvest time begins in early summer and often many fruits form quickly. Keep reading for our tips on harvesting and storing courgettes.