How to Grow Courgettes in the UK

How to Grow Courgettes in the UK: Complete Growing Guide

Courgettes (zucchini) are prolific, easy-to-grow vegetables that thrive in the UK climate. With their vigorous growth and abundant harvests, a few plants can keep you supplied with fresh courgettes throughout summer.

Not sure when to sow? See our When to Plant Courgettes UK →

Quick Growing Facts

Sowing Time: April to May indoors; May to June outdoors
Harvest Time: July to October
Growing Time: 8-12 weeks from sowing to first harvest
Difficulty: Easy
Position: Full sun, sheltered

When to Sow Courgettes

Indoor sowing: April-May in pots or modules for transplanting after last frost
Outdoor sowing: Late May-June when soil has warmed and frost risk has passed
Transplanting: Plant out in late May-early June after hardening off
Succession sowing: Sow 2-3 times at 2-week intervals for extended harvest

Soil Preparation

Soil type: Rich, moisture-retentive but well-drained soil
Add organic matter: Dig in plenty of well-rotted manure or compost
Create planting pockets: Dig holes 30cm (12 inches) deep and wide, fill with compost
pH level: Slightly acidic to neutral (pH 6.0-7.0)
Warm soil: Ensure soil temperature is at least 12°C before planting out

How to Sow Courgettes

Indoor Sowing (recommended for UK):

Use large pots: Sow in 7.5cm (3 inch) pots or modules filled with seed compost
Sow on edge: Push seeds 2.5cm (1 inch) deep on their edge to prevent rotting
One seed per pot: Sow one seed per pot as germination rates are high
Warmth needed: Keep at 20-25°C for germination (7-10 days)
Good light: Move to bright, frost-free location once germinated
Pot on if needed: Transfer to larger pots if plants outgrow modules before planting out

Direct Outdoor Sowing:

Only suitable for late May-June in warm, sheltered locations
Sow 2-3 seeds per station, 90cm (3 feet) apart
Thin to strongest seedling once established
Protect with cloches or fleece until established

💡 Top Tip

Courgettes don't like root disturbance. Sow in biodegradable pots that can be planted directly into the ground, or use large modules and transplant carefully with the entire root ball intact.

Planting Out

Harden off: Acclimatise plants to outdoor conditions over 7-10 days
After last frost: Plant out only when all frost risk has passed (late May-early June)
Spacing: Space plants 90cm (3 feet) apart in all directions
Plant level: Plant at the same depth as in the pot
Water well: Water thoroughly after planting
Protect initially: Use cloches or fleece for first few weeks if weather is cool

Ongoing Care

Watering: Water generously and regularly, especially when flowering and fruiting; aim for 20 litres per plant per week in dry weather
Feeding: Feed weekly with high-potash liquid fertiliser once flowering begins
Mulching: Apply thick mulch around plants to retain moisture and suppress weeds
Weeding: Keep weed-free, but be careful not to damage shallow roots
Support fruits: Place a tile or board under fruits to prevent rotting on damp soil

Common Problems

Poor fruit set: Often due to lack of pollinating insects. Hand-pollinate by transferring pollen from male flowers (thin stem) to female flowers (swollen base) using a soft brush.

Powdery mildew: White powdery coating on leaves. Ensure good air circulation, water at base of plants, and remove affected leaves.

Rotting fruits: Caused by contact with damp soil or poor pollination. Raise fruits off ground and ensure proper pollination.

Slugs and snails: Can damage young plants. Protect with barriers, traps, or organic pellets.

Harvesting Courgettes

Timing: First harvest usually 8-12 weeks after sowing
Size: Harvest when 10-15cm (4-6 inches) long for best flavour and texture
Pick regularly: Check plants every 2-3 days and harvest all ready fruits
Cut cleanly: Use a sharp knife to cut fruits with a short stem attached
Don't let them grow large: Large courgettes (marrows) reduce plant productivity
Flowers edible: Male flowers can be harvested and eaten (stuffed and fried)