How to Sow Sweet Peas in Autumn for a Stunning Summer Display

Sweet peas are among the most charming and fragrant flowers you can grow in your garden. By sowing sweet peas in autumn, you give them a head start, allowing them to establish strong roots over the winter and reward you with abundant blooms early in summer. Growing these delightful climbers is simple and hugely rewarding, with a few key tips that will help ensure success. Here’s how to get started with sowing your sweet peas this autumn.

Why Sow Sweet Peas in Autumn?

Sowing sweet peas in autumn offers several advantages:

• Stronger Plants: The roots have more time to develop, producing healthier and more vigorous plants.
• Earlier Blooms: Autumn-sown sweet peas tend to flower earlier, giving you a head start on the growing season.
• Increased Fragrance and Size: Many gardeners find that autumn-sown sweet peas produce larger blooms and a more intense fragrance.

Choosing the Right Variety

Before sowing, decide what kind of sweet peas you’d like to grow. If fragrance is your priority, go for traditional varieties such as ‘Kings Cupid Mix’ or ‘Kinds Incense Mix.’ If you’re more interested in larger blooms and vibrant colors, there are plenty of modern hybrids that will do the job. Many sweet peas are climbing varieties that will need support, but there are also dwarf types that are ideal for containers or smaller spaces.

How to Sow Sweet Peas in Autumn

Sowing in autumn is all about giving your plants a head start while protecting them from the cold. Here’s a step-by-step guide:

1. Soak the Seeds: Sweet pea seeds have hard outer shells, which can make germination slow. To help speed up the process, soak the seeds in water overnight before planting. This softens the seed coat and encourages quicker sprouting.

2. Choose Your Containers: You can start sweet peas in pots, root trainers, or deep containers. Sweet peas develop long roots, so the deeper the container, the better. Root trainers are ideal, as they allow for easy transplanting without disturbing the roots.

3. Use Well-Draining Compost: Fill your containers with a high-quality, well-draining compost. Plant the seeds about 1-2cm deep and space them out to give each plant room to grow. If using smaller pots, you can plant one or two seeds per pot.

4. Keep Them Cool: Sweet peas don’t need warmth to germinate. In fact, they prefer cooler conditions, so place your pots in an unheated greenhouse, cold frame, or sheltered spot outdoors. If you're concerned about frost, cover the seedlings with fleece or a cloche to protect them. If you don't have a greenhouse, a sunny windowsill in a cool room can also work well.

5. Water Sparingly: While it’s important to keep the compost moist, don’t overwater. Sweet peas dislike sitting in waterlogged soil, so water gently and allow the compost to dry out slightly between waterings.

6. Pinch Out for Bushier Plants: Once your sweet pea seedlings reach about 4 inches in height, pinch out the tips. This encourages the plants to become bushier, with more side shoots and, ultimately, more flowers.

Caring for Sweet Pea Seedlings Over Winter

Throughout the winter months, your sweet pea seedlings will slowly establish strong root systems. Keep them in a cool, frost-free location, and water sparingly. As the days get longer and warmer in early spring, your plants will begin to take off.

Planting Out in Spring

When the risk of frost has passed in spring, you can plant your sweet peas out into their final growing positions. Choose a sunny spot with well-drained soil, and make sure you have sturdy supports in place. Sweet peas love to climb, so providing a trellis, netting, or a wigwam of canes will give them plenty of room to scramble upwards.

Key Care Tips for Spring and Summer

• Support Growth: As your sweet peas grow, tie them in regularly to their supports. This ensures the plants stay upright and get plenty of air circulation.
• Water Regularly: Sweet peas are thirsty plants, especially once they start to flower. Water them consistently, particularly during dry spells, to keep them blooming.
• Feed Them: Once your sweet peas are established, feed them with a high-potash fertilizer (such as tomato feed) every couple of weeks to encourage more flowers.
• Deadhead Regularly: To keep the flowers coming, make sure you deadhead faded blooms regularly. You can also cut flowers for the house – the more you pick, the more they’ll bloom.

Enjoy the Rewards

By sowing sweet peas in autumn, you’ll be rewarded with vigorous plants that flower earlier and longer. Their intoxicating fragrance and cheerful colours will fill your garden, and if you cut the flowers, you’ll have the pleasure of their scent indoors as well. Growing sweet peas is a simple yet satisfying way to bring beauty into your outdoor space, so grab some seeds and start sowing!

With a little care over the winter, your autumn-sown sweet peas will thrive, giving you a head start on a glorious summer garden.