What’s the best time of year to sow sweet peas and when should you plant them out in your garden?

By Daniel Graham

Published: Friday, 06 October 2023 at 06:42 AM


The sweet pea (Lathyrus odoratus) is an annual climber with numerous mid to dark green leaves and fragrant flowers.

A member of the genus Lathyrus (everlasting pea), the sweet pea is native to Sicily, southern Italy and the Aegean Islands. Yet depsite this it is a favourite of many gardeners in the UK. And who can blame them? From summer to early autumn, sweet peas offer an explosion of colour, structure and perfume to any garden, and can be grown over hedges, up walls or as bushes.

Sweet peas are also one of the best garden plants to grow as cut flowers – not only do their delicate flowerheads look beautiful in arrangements, but the act of cutting off the flowers promotes the growth of new blooms on the plant.

Looking to add sweet peas to your garden? Find out the best time to sow them and when to plant them out with our quick guide.

Sow sweet peas seeds between mid autumn and mid spring/Credit: Getty

When to sow sweet peas?

The best time to sow sweet pea seeds in the UK is between mid autumn and mid spring – October to April.

Ideally you should plant your sweet peas is late October and November or late February and March. You can sow them in mid winter but with low temperatures and light levels, you’re less likely to produce strong, healthy plants.

Towards the end of spring (April to May), when the soil is starting to warm, sweet peas can be sown directly into the ground.

Sweet pea seedlings in a greenhouse
Sweet pea seedlings are best planted out in May or June/Credit: Getty

When to plant out sweet peas?

Once your sweet pea seedlings have strong, healthy shoots, they’re ready to plant out. It’s important to wait for a mild spell (once the risk of frost has passed) between May and June to do this.

Plants should be hardened off before planting out. This means putting them outside in the daytime when temperatures are warm and bringing them in at night to protect them against the cold.

For strong, bushy growth, pinch out the tips of the young plants (10cm tall).