The Complete Guide on How to Grow Courgettes

Have you ever grown courgettes? Have you ever tried? Courgettes, or zucchini as our American cousins call them, are members of the cucurbit family. They’re essentially marrows harvested young, though modern varieties have been bred specifically for picking at this immature stage. In my experience, a single well-maintained plant can produce upwards of 20 fruits across the growing season, making them brilliant value for the space they occupy. They’re hungry, thirsty plants that reward attention with generous harvests, but they won’t tolerate neglect or poor conditions. If you’ve struggled with courgettes before, it’s almost certainly down to one of a handful of common issues that are entirely fixable. Lets look at how we can grow courgette’s.

The good news is that once you understand how to grow courgettes properly, you’ll find them remarkably reliable. They germinate readily, grow rapidly, and fruit prolifically. The challenge isn’t getting them to produce, but rather keeping up with the harvest once they get going. Let me walk you through everything I’ve learned from years of growing these productive plants in various British gardens. If you are enjoying our content you may also find our article about fennel interesting: from seed to harvest: growing fennel in your garden.

How to Grow Courgettes

Before you start, gather everything together. Courgettes aren’t fussy, but having the right materials makes the process much smoother.

Seeds and Growing Medium

You’ll need courgette seeds from a reliable source. I prefer buying fresh seed each year rather than saving my own, as commercial seed has better germination rates and disease resistance. For starting seeds, use a good quality seed compost. Avoid garden soil or multipurpose compost for germination, as these can be too heavy and may contain damping-off pathogens that kill seedlings.

You’ll also need 7.5cm pots for initial sowing and larger 9cm or 10cm pots for potting on. I use biodegradable pots sometimes, which can go straight into the ground, though they’re not essential. A heated propagator or warm windowsill is useful but not strictly necessary if you time things right. You might also find from seed to harvest: growing perfect tarragon at home helpful.

Site Preparation Materials

For the growing site, you’ll need well-rotted manure or garden compost in generous quantities. Courgettes are greedy feeders, and I’ve found that a bucketful of organic matter per planting hole makes an enormous difference. You’ll also want a general-purpose organic fertiliser for mixing into the soil, and ideally some liquid feed for later in the season.

If you’re growing in containers, choose pots at least 45cm in diameter. Smaller pots dry out too quickly and restrict root growth, leading to poor yields. You’ll need a decent multipurpose compost mixed with some garden compost if you have it.

Step-by-Step Instructions

Sowing Your Seeds

I start sowing courgettes in mid-April for planting out after the last frosts, which typically means late May in southern England or early June further north. Don’t be tempted to sow too early. Courgettes grow quickly and hate being pot-bound, so there’s no advantage to starting them in March.

Fill your pots with seed compost and firm gently. Push one seed into each pot on its edge about 2cm deep. This edge-sowing trick reduces the risk of rotting. Water gently and place somewhere warm, ideally 18-21°C. I’ve germinated courgettes successfully on top of the fridge, in an airing cupboard, and on sunny windowsills. They’ll typically germinate within five to seven days.

Once the seedlings emerge, move them to a bright spot but not scorching direct sunlight, which can scorch tender leaves. A greenhouse, cold frame, or south-facing windowsill works well. Keep the compost moist but not waterlogged.

Potting On and Hardening Off

When your seedlings have developed their first true leaves (the ones that look like proper courgette leaves, not the initial seed leaves), pot them on into larger containers if they’re looking cramped. This usually happens around two weeks after germination.

About ten days before planting out, start hardening off your plants. This means gradually acclimatising them to outdoor conditions. I put mine outside during the day and bring them in at night for the first few days, then leave them out in a sheltered spot unless frost threatens. This process toughens up the plants and prevents the shock of sudden transplanting.

Preparing the Planting Site

Whilst your seedlings are growing, prepare your planting site. Courgettes need full sun for at least six hours daily and shelter from strong winds. I’ve grown them successfully in raised beds, directly in the ground, and in large containers on a patio.

Dig a hole about 30cm wide and deep for each plant, spacing them at least 60cm apart. Some varieties need even more space. Fill each hole with well-rotted manure or garden compost, then mix this thoroughly with the excavated soil. Courgettes appreciate rich soil, and this preparation makes all the difference to later growth.

Planting Out

Wait until all risk of frost has passed before planting out. In my Hampshire garden, this is usually around the last week of May, but in Scotland or northern England you might need to wait until mid-June. Check local frost date information for your area.

Plant in the evening or on an overcast day to reduce transplant stress. Water your seedlings thoroughly an hour before planting. Dig a hole the same depth as the pot and carefully remove the plant, keeping the root ball intact. Courgettes don’t like root disturbance. Place the plant in the hole so the compost surface is level with the surrounding soil, firm gently, and water well.

I often create a slight depression around each plant to help water pool around the roots. Some gardeners mound the soil up instead, which can help with drainage on heavy clay, but I’ve found the depression method works better on my free-draining soil.

Watering and Feeding

Here’s where many people go wrong. Courgettes need consistent moisture, particularly once they start flowering and fruiting. I water deeply two or three times weekly during dry spells, giving each plant at least two full watering cans. Light, frequent watering encourages shallow roots, so it’s better to water thoroughly less often.

Try to water at the base of plants rather than overhead. Wet foliage encourages powdery mildew, which courgettes are prone to anyway. I water in the morning so any splash on leaves can dry during the day.

Start feeding once flowers appear. I use a high-potash liquid feed, the sort you’d use for tomatoes, every week or two. This supports fruit development. Too much nitrogen-rich feed produces lots of leaves but fewer courgettes.

Pollination and Fruit Development

Courgettes produce separate male and female flowers on the same plant. Male flowers appear on long thin stems, whilst female flowers have a small swelling behind the petals that becomes the courgette. Early in the season, plants often produce only male flowers. Don’t panic, this is normal. Female flowers will follow.

In a good year with plenty of bees, pollination happens naturally. However, I’ve had summers in my Berkshire garden where cool, wet weather kept pollinators away. When this happens, you can hand-pollinate by picking a male flower, removing its petals, and dabbing the pollen-covered centre onto the centre of female flowers. It feels slightly absurd but works brilliantly.

Harvesting

Start harvesting when fruits reach 10-15cm long. At this size, they’re tender and flavourful. Left longer, they become watery and full of seeds. I check plants every couple of days during peak season, as courgettes can balloon from perfect to oversized in 48 hours.

Cut fruits with a sharp knife, leaving a short stem attached. Regular harvesting encourages more production, so even if you’re drowning in courgettes, keep picking. I’ve given away countless bags to neighbours and allotment friends in July and August.

Common Mistakes to Avoid

Planting Too Early

The single biggest mistake I see is planting out before conditions are right. Courgettes are frost-tender and sulk in cold soil. Even if they survive a late cold snap, their growth is set back and they never quite recover. Better to plant a week late than a day too early. If you’re unsure, wait until other gardeners in your area are planting out their tender crops.

Similarly, don’t sow seeds too early indoors. Leggy, pot-bound plants produce poorly. A courgette sown in late April and planted out in late May will overtake one started in March, I’ve tested this multiple times.

Inconsistent Watering

Courgettes hate irregular watering. Let them dry out, then flood them, and you’ll get blossom end rot, where the flower end of fruits turns black and mushy. You’ll also get poor fruit set and stressed plants vulnerable to pests and diseases. I learned this the hard way during a particularly busy period when I neglected my allotment plot for a fortnight. The plants survived but produced perhaps a quarter of their normal crop.

If you’re growing in containers, this becomes even more critical. Pots dry out rapidly in hot weather, sometimes needing water twice daily. This is why I recommend the largest containers you can manage.

Ignoring Powdery Mildew

That white, powdery coating on leaves isn’t just unsightly, it reduces photosynthesis and weakens plants. Many gardeners assume it’s inevitable and do nothing, but you can minimise it by ensuring good air circulation, watering at the base of plants, and removing affected leaves promptly. I’ve found that mulching around plants helps maintain consistent soil moisture, which in turn seems to reduce mildew susceptibility.

Poor Soil Preparation

Courgettes planted in unimproved soil struggle to produce well. I visited an allotment in Bristol where a frustrated gardener was getting perhaps three courgettes per plant. The soil was poor, compacted clay with no organic matter. After discussing soil preparation, the following season brought a dramatic improvement. These plants need feeding, and whilst you can supplement with liquid feeds, nothing beats proper soil preparation from the start.

Expert Tips

Variety Selection Matters

Not all courgette varieties perform equally in British conditions. I’ve had excellent results with ‘Defender’, which shows good mildew resistance, and ‘Midnight’, a dark green variety that crops reliably. Yellow varieties like ‘Golden Zucchini’ are fun for variety but in my experience crop slightly less heavily. Climbing varieties exist but need sturdy support and aren’t necessarily more productive than bush types, just more vertical.

For small spaces, look for compact varieties specifically bred for container growing. These occupy less ground space whilst still producing decent crops.

Succession Sowing

Rather than sowing all your courgettes at once, try succession sowing. I sow a first batch in mid-April, then another in early May. This extends the harvest period and provides backup if early plants succumb to slugs or other problems. The later sowing often crops into October if conditions are mild, whilst early plants can become tired and mildew-ridden by late summer.

Mulching Works Wonders

Once plants are established and the soil has warmed, apply a 5-10cm mulch of garden compost, well-rotted manure, or even grass clippings around plants. This suppresses weeds, conserves moisture, and gradually feeds the soil as it breaks down. I’ve noticed that mulched plants cope better with dry spells and seem to have fewer pest problems, possibly because the mulch provides habitat for ground beetles and other beneficial insects.

Watch for Pests

Slugs love courgette seedlings. Protect young plants with whatever method you prefer, whether that’s organic pellets, copper tape, or evening patrols with a torch. Once plants are established, they’re usually too tough for slugs to bother with.

Aphids occasionally cluster on growing tips. I squash small infestations by hand or wash them off with a jet of water. Serious infestations are rare if you encourage natural predators like ladybirds and hoverflies by growing flowers nearby.

Don’t Waste the Flowers

Courgette flowers are edible and delicious. Male flowers, which the plant produces in abundance, can be picked without affecting cropping. Stuff them with ricotta and herbs, then bake, or dip in batter and fry. They’re a delicacy in Italian cooking and increasingly popular at farmers’ markets across Kent and Sussex. If you’re not using them, leave them for the bees.

Frequently Asked Questions

Why are my courgette plants producing flowers but no fruit?

This happens for several reasons. Early in the season, plants often produce only male flowers, which can’t develop into fruit. Female flowers, recognisable by the small swelling behind the petals, will follow once the plant is more established. If you’re getting female flowers but they’re turning yellow and dropping off, pollination isn’t happening. This can be due to cold, wet weather keeping bees away, or simply a lack of pollinators in your area. Hand-pollinate by transferring pollen from male to female flowers using a small brush or by dabbing the flowers together. I’ve also seen poor fruit set when plants are stressed by irregular watering or nutrient deficiency. Make sure you’re feeding and watering consistently once flowering begins.

How often should I water courgette plants?

Courgettes need consistent moisture, particularly during flowering and fruiting. In my garden, I water deeply two to three times weekly during dry weather, giving each plant about 10 litres of water per session. It’s better to water thoroughly less often than to sprinkle lightly every day, as deep watering encourages strong root growth. Container-grown plants dry out much faster and may need daily watering in hot weather, sometimes even twice daily. The soil should remain moist but not waterlogged. I check by pushing my finger into the soil, if it’s dry below the surface, it’s time to water. Always water at the base of plants rather than overhead to reduce the risk of fungal diseases.

Can I grow courgettes in pots?

Absolutely, and I’ve had good success with container-grown courgettes on patios and balconies. The key is using large enough pots, at least 45cm in diameter and depth. Smaller containers simply don’t hold enough compost or moisture to support these vigorous plants. Fill pots with a good quality multipurpose compost mixed with some garden compost or well-rotted manure for extra nutrients. Container plants need more frequent watering and feeding than those in the ground because nutrients leach out with repeated watering. I feed container courgettes weekly with a liquid fertiliser once they start flowering. Choose compact varieties if you’re tight on space, as some courgettes can spread over a metre across.

What’s the white powder on my courgette leaves?

That’s powdery mildew, a fungal disease that affects courgettes, particularly in late summer. It appears as white, powdery patches on leaves and stems, eventually causing leaves to yellow and die. Whilst it’s common and rarely kills plants outright, it does reduce vigour and cropping. You can minimise mildew by ensuring good air circulation around plants, watering at the base rather than overhead, and maintaining consistent soil moisture as stressed plants are more susceptible. Remove badly affected leaves and dispose of them, don’t compost them. Some varieties show better resistance than others. I’ve found that plants growing in rich, well-prepared soil with adequate spacing suffer less than those in poor conditions. Organic fungicides are available but prevention is better than cure.

When should I pick courgettes for the best flavour?

Harvest courgettes when they’re 10-15cm long for the best texture and flavour. At this size, they’re tender with small seeds and thin skin. Left longer, they become watery and develop large seeds and tough skin. During peak season, I check plants every two days because courgettes can grow remarkably quickly in warm weather. If you miss one and it grows into a marrow-sized monster, don’t worry, you can still eat it. Just scoop out the seeds, peel off the thick skin, and use the flesh in soups or bakes. However, leaving oversized fruits on the plant diverts energy from producing new courgettes, so keep picking regularly. Cut fruits with a sharp knife, leaving a short stem attached. The more you pick, the more the plant produces, so even if you’ve got more than you can use, keep harvesting and share with friends or neighbours.

Why are the ends of my courgettes rotting?

This is blossom end rot, caused by calcium deficiency in the developing fruit. However, it’s rarely due to lack of calcium in the soil. Instead, it’s usually caused by irregular watering, which prevents the plant from taking up calcium effectively. The condition appears as a brown, sunken, rotten patch at the flower end of fruits. I’ve experienced this during particularly dry spells when I couldn’t maintain consistent watering. To prevent it, ensure regular, thorough watering, particularly during fruit development. Mulching helps by maintaining more consistent soil moisture. Once affected fruits appear, remove and dispose of them as they won’t recover. Future fruits should be fine if you improve your watering regime. In containers, this problem is more common because pots dry out quickly, so pay extra attention to watering if you’re growing courgettes in pots.

Final Thoughts

Growing courgettes successfully comes down to understanding what these vigorous plants need and providing it consistently. They’re not difficult, but they won’t tolerate neglect or poor conditions. Give them rich soil, plenty of water, regular feeding, and warm weather, and they’ll reward you with an abundant harvest that might leave you frantically searching for new recipe ideas come July.

I’ve found them to be one of the most satisfying vegetables to grow because the return on effort is so high. A few plants provide more than enough for most families, with plenty left over for sharing. The taste of a freshly picked courgette, sliced and simply grilled with olive oil and garlic, bears little resemblance to the watery specimens often found in shops.

If you’re new to vegetable growing, courgettes are a brilliant place to start. They germinate reliably, grow quickly enough to maintain your interest, and produce tangible results within a few months of sowing. Even experienced gardeners find them rewarding because there’s always something new to learn, whether that’s trying a different variety, experimenting with training methods, or perfecting your soil preparation technique.

The key is to start small, perhaps with just two or three plants, and build your knowledge from there. Pay attention to what works in your particular garden, because conditions vary enormously across the country. What succeeds in a sheltered Devon garden might need adjusting for an exposed Yorkshire allotment. Keep notes, observe your plants, and don’t be discouraged by setbacks. Every gardener has lost plants to unexpected frosts, slug attacks, or mysterious wilts. It’s all part of the learning process, and each season brings new opportunities to improve your technique.

Author: Megan Walker

Megan focuses on seasonal food, kitchen garden growing, and how households can reconnect with where their food comes from. Her writing blends practical growing advice with ideas for cooking and eating in season. With a passion for fresh ingredients and sustainable living, Megan’s articles help readers make the most of local produce while supporting British farms.