When to Sow Sweet Peas: The Benefits of Autumn and Spring Sowing
Why I Sow Sweet Peas in Autumn and Spring
If you’ve been following my gardening projects for a while, you’ll know I have a bit of a soft spot for sweet peas. Their scent, their colours, and the way they scramble up trellises or wigwams just make the garden feel alive. Over the years, I’ve found that sowing twice a year, once in autumn and again in early spring, gives the best display possible.
Sowing sweet peas in October gives your plants a head start. The seeds germinate and grow slowly through the cooler months, developing strong root systems and sturdy plants ready to burst into life as soon as spring arrives. These in the photo were sown at the just ten days ago, and they're already excited to show me what they're capable of (Tip: don’t let them get too tall at this stage. Keep them trimmed to about 10m tall. You’ll prevent them from getting too leggy, and you’ll get more blooms in the spring)
By late May or early June, autumn-sown sweet peas are often the first to flower, weeks before the spring-sown ones catch up. These early blooms are perfect if you love cutting fresh flowers for the house or want your garden full of colour early in the season. (Tip: Keep them in a cold frame, greenhouse, or sheltered spot outdoors. They don’t mind a bit of cold, but harsh frost can damage young plants.) This autumn sown seed’s first flower was excited to arrive mid-April of last year.
In February or March, I sow another batch. These seedlings grow quickly with the increasing light and warmth, and they’ll come into flower just as the autumn-sown plants start to fade. The result is a continuous display of sweet peas from late spring right through to the end of summer. Spring sowing is also a great backup plan. If your autumn seedlings get nibbled by slugs or don’t make it through a cold snap, the spring ones will fill in the gaps beautifully.
By sowing twice, you spread your risk and extend your reward. Autumn sowing gives you strong, early plants, while spring sowing gives you fresh, vigorous growth later. Together, they keep your garden scented and colourful for months.
Whether you start your seeds in root trainers, pots, or even recycled loo rolls, sweet peas are wonderfully forgiving. Give them good light, well-drained compost, and a little patience, and they’ll repay you tenfold with their charm and perfume. So, try it. Sow some in October and some in early spring. Once those first blooms appear I promise you’ll be glad you did!