When to sow courgettes for your most productive summer crop yet

Courgettes are rewarding crops, and they'll earn you a glut in no time. But to get them started, you’ll need to know when to sow courgettes.

Learning how to grow courgettes is a piece of cake – they grow quickly, and they’re great for beginners. You can get started now, but the rules around when to sow courgettes depend on where you’ll be planting the seeds.

We’ve broken down the indoor and outdoor sowing timeframes to help you get your timing right.

Where to buy courgette seeds

• D.T. Brown: Shop green, yellow and even spherical courgette seeds.
• Mr Fothergill's: Another brilliant selection of courgette seeds to choose from.
• Thompson & Morgan: Courgette 'Defender' F1 Hybrid is a popular choice.

When to sow courgettes outdoors

If you’re keen to sow courgettes outdoors this month, you’ll need to hold your horses. These plants are tender by nature, and it’s a little too soon to plant the seeds outdoors directly.

‘Wait until the chance of low temperatures and frost has passed,’ advises Lucie Bradley, gardening and greenhouse expert at Easy Garden Irrigation. ‘In most areas of the UK, this is from the middle of May onwards.’

To be sure, you can use a soil thermometer like this garden soil thermometer probe from Amazon. ‘If you can take the temperature of your soil, you are looking at a soil temperature of 10°C and above to sow successfully,’ explains Rachel Cole, horticulturist at D.T. Brown.

Lucie Bradley

Encouraged to garden since she was old enough to walk, Lucie has been working in the gardening industry for over 28 years. This has meant she has been lucky enough to talk to both amateur and professional gardeners every day of the week and is always learning. She believes you can never know everything about gardening as it constantly evolves.

If you’re hoping to grow courgettes in pots, the soil should be a little warmer than the ground.

You’ll still need to keep an eye out for any late frosts or temperature drops during the night, though – and it’s a good idea to have a cloche (like this one from Amazon) to hand just in case (or work out what you can use in a garden instead of a cloche if you’re on a budget).

‘You still need to be on the lookout for drops in overnight temperature and have cloches or horticultural fleece on hand to cover the planted area,’ Lucie explains.

When to sow courgettes indoors

For an earlier crop, you can sow courgettes indoors much earlier in the year – in a greenhouse, a polytunnel, or even a windowsill.

‘You can sow courgettes indoors from March until May in small pots of compost,’ says Rachel. ‘Courgettes are fast germinators, and seedings will appear in around seven to 14 days.’

So, if you've been wondering what to plant in March, you can add these fast-croppers to your list.

FAQs

When can I put courgette plants outside in the UK?

After you’ve started your courgettes off indoors, you’ll need to think about the best time to transplant them outside.

‘Courgettes are incredibly fast growing and will be ready to plant out in situ from indoor sowings after four weeks,’ explains Rachel from D.T. Brown.

‘Do accustom the plants to the outside gradually and, ideally, plant out after the risk of frosts is over.’

Do slugs eat courgettes?

Yes! Sadly, slugs enjoy courgettes as much as we do – so it’s worth looking for natural ways to get rid of slugs before you get started.

So – March gives us the green light for indoor sowings, and mid- to late May is a good time to start sowing outdoors. Just watch out for those late frosts!