When to sow sweet peas outdoors — and how to create the perfect growing spot to ensure they thrive

Sweet peas are among the prettiest and, well, sweetest blooms you'll find in the garden. And as we find ourselves approaching spring, you’re probably wondering when to sow sweet peas outdoors.

Learning how to grow sweet peas from seed starts with planting them at the right time — and if you’re planning on sowing them outdoors, timing is crucial to successful germination. It’s slightly different to the rules around when to sow sweet peas indoors, that’s for sure.

We’ve asked the experts when to sow sweet peas outdoors to make sure we’re getting the seeds off to the very best start.

So — when to sow sweet peas outdoors, then?

It all comes down to when the last frosts in your area are — but you’ll need to try and avoid them for the best results.

‘For the best possible success, sweet peas should be directly sown outdoors once the risk of hard frost has passed and the soil has started to warm up — typically in April and May,’ says Jane Westoby, creative director at The Hampshire Seed Company.

‘Although they can tolerate a light late spring frost, it’s best to sow hardy annuals between late March and May, as the soil begins to warm up,’ agrees Jamie Shipley, gardening expert and managing director at Hedges Direct.

Once you've decided when you're going to sow your sweet peas outdoors, you'll need to get your garden ready for sowing...

What to do before sowing sweet peas outdoors

Now you know when to sow sweet peas outdoors, there are a few things you should take care of first to ensure your plants thrive.

‘Before thinking about when to sow sweet peas outdoors, it’s important to prepare the area for planting,’ says Hannah Rowson, garden centre manager at J.Parker’s.

How do we do that? ‘Choose a well-drained, sunny spot, digging in plenty of organic matter, as sweet peas are hungry plants,’ says Jane from The Hampshire Seed Company. So, if you’ve been learning how to make compost, now’s the perfect time to put it to use.

You’ll also need to think about how you’re going to support the plants if you want to care for sweet peas properly — they're one of the fastest-growing climbing plants for privacy, after all.

‘Because sweet peas grow quite tall, they need support, whether that’s in the shape of a trellis or a homemade wigwam,’ says Hannah.

Where to buy sweet pea supports:

FAQs

Can I grow sweet peas in containers?

Yes! If you don’t have the space in borders, you can learn how to grow sweet peas in pots. But you need to provide them with the right planter, soil and spot.

‘Provide them with a good sunny location and peat-free compost that’s combined with a slow-release fertiliser,' advises Petar Ivanov, gardening expert at Fantastic Gardeners.

You'll also need select a container that's big enough. ‘Choose a deep enough container to house the large root system of a sweet pea comfortably,' advises Jamie from Hedges Direct. 'You’ll need a pot at least 20 centimetres deep, and it’s best to choose a long, narrow pot to help the roots establish a deep system.’

Now you know when to sow sweet peas outdoors, you can start ordering in your seeds...