Courgettes are easy to grow once the weather warms, but planting them too early can leave young plants sitting in cold soil and struggling to get going.
In the UK, sow courgettes indoors from mid to late April and plant them outside from late May into June, once the risk of frost has passed. You can also sow directly outdoors from late May or June when the soil is warm.
Courgette Planting Timeline: UK Month-by-Month
Courgettes need warmth, so there is little benefit in starting them too early. For most UK gardeners, April to June is the useful planting window.
| Month | What to do |
|---|---|
| March | Usually too early. Sow only if you can provide reliable warmth and good light. |
| April | Start seeds indoors, ideally from mid to late April. Keep seedlings bright, warm and frost-free. |
| May | Continue growing plants indoors and harden them off towards the end of the month. Plant outside only once frost risk has passed. |
| June | Plant courgettes outside or sow directly into warm soil. This is the safest option in cooler areas. |
BYF Chosen Variety – Courgette Defender F1 AGM
A reliable early-cropping courgette with good disease resistance and an open habit that makes harvesting easy. A strong all-round choice for beds, raised beds and allotments.
Indoor vs Outdoor Sowing
You can sow courgettes indoors or directly outside, but in the UK the main difference is timing.
Sow Indoors
Indoor sowing is the most reliable option early in the season.
- Sow from mid to late April
- Keep seedlings somewhere bright and frost-free
- Harden them off before planting outside
Starting too early can leave you with large, leggy plants before conditions outside are suitable.
Sow Outdoors
Courgettes can also be sown directly into the ground once the soil has warmed.
- Sow outdoors from late May to June
- Choose a warm, sheltered spot
- Protect young seedlings from slugs and snails
Direct-sown plants start later, but they can establish quickly in warm conditions.
Which Is Best?
For most UK gardeners, starting a few plants indoors gives the earliest reliable crop, while direct sowing is a simple option once the weather warms.
You can also use both methods if you want a later backup sowing.
Once your plants are established, see our guide to growing courgettes in the UK for watering, feeding and ongoing care.
Is It Too Late to Plant Courgettes?
Usually, no. Courgettes grow quickly once conditions are warm, so later planting can still work well.
- May: Not too late at all. Late May is often ideal for planting outside.
- June: One of the safest and most reliable times to plant courgettes in the UK.
- July: Still possible, although the cropping season will be shorter.
- August: Much less reliable. Established plants may still produce, but new sowings are unlikely to give a worthwhile crop in many areas.
Courgettes planted into warm soil and settled weather can establish quickly and sometimes catch up with plants put out too early.
If you still have healthy young plants in June or early July, it is usually worth planting them out.
Once plants begin producing, see when to harvest courgettes for the best picking size and signs they are ready.
Common Courgette Planting Mistakes
Most problems when planting courgettes come from putting them out too early or before the plants are ready.
| Mistake | What happens | Better approach |
|---|---|---|
| Planting too early | Cold soil and chilly nights can stall growth. | Wait until frost risk has passed and conditions have warmed. |
| Planting weak seedlings | Small plants are more vulnerable to cold, wind and pests. | Plant out sturdy, established courgettes rather than very young seedlings. |
| Skipping hardening off | Indoor-grown plants can wilt or stall when moved straight outside. | Harden plants off gradually for around 7–10 days. |
| Ignoring slugs and snails | Young courgettes can be badly damaged soon after planting. | Protect plants while they establish and check them regularly. |
A little patience makes the biggest difference. Strong, hardened-off plants put into warm conditions are much more likely to establish quickly.
Plan Your Courgettes Before You Plant
Courgettes need more room than you might expect, so it helps to work out where they’ll go before planting. Use the free BYF Allotment Planner to lay out your beds, check crop spacing and see what else you can fit around them.
FAQs
You can sow courgettes indoors in April, but it is usually too early to plant them outside. Wait until the risk of frost has passed and conditions have warmed.
For most UK gardens, late May to June is the main planting window. Harden plants off first and wait until frost risk has passed.
Yes. Sow courgettes directly outside from late May to June, once the soil has warmed. Protect young seedlings from slugs and snails.
No. June is an excellent time to plant courgettes and can be more reliable than putting them out too early into cold soil.
Yes, especially if you already have young plants ready to go. They can still produce a useful crop, although the harvesting period will be shorter.
Yes. Courgettes raised indoors should be hardened off gradually for around 7–10 days before planting outside.
