Sow Sweet Peas in Autumn for Stronger Plants, Earlier Flowers, and a Longer Flowering Season
Sweet peas are one of the high points of the flower-growing season, and sowing your sweet peas in autumn can lead to stronger plants, larger flowers, longer stems, and an extended flowering season.
What Are The Benefits of Sowing Sweet Peas in Autumn?
Sweet peas sown in autumn give a number of advantages due to the extended time they have to develop. Sweet peas are generally annuals (completing their life cycle in a year). But sowing them in autumn gives your seeds a few extra months to establish. This helps them in the following ways:
- Stronger root systems - as they grow steadily through autumn and winter, the plants will develop substantial root systems before they start putting energy into top growth when the temperatures rise.
- Earlier flowering – sweet peas that have been established before winter will really start growing as everything warms up in the spring. They will often flower 2-4 weeks earlier than spring-sown sweet peas. With the dry summers that we’ve had over the last few years, this early flowering also means that you will get good, established flowers before the weather gets too hot and dry.
- More vigorous plants - with established root systems already in place, autumn-sown sweet peas are well equipped to put on strong, healthy growth when conditions improve in spring. This vigorous growth can also contribute to larger flowers and bigger plants.
- More flowers – a longer growing and flowering season generally brings more flowers with it, as long as you keep cutting and deadheading.
- Longer stems for cutting – because autumn-sown sweet peas are already established, they can begin developing their flowering stems during the cooler spring weather. These cooler growing conditions can encourage longer stems, making them an excellent choice for cut flower arrangements.
How to Sow Sweet Peas in Autumn
The process for sowing sweet peas in autumn is very similar to sowing them in spring, but there are a few things to be mindful of. In the UK, sweet peas sown in autumn are typically started during October and November. Over winter, you are aiming to develop strong root systems with limited top growth.
1. Sow your sweet pea seeds in good-quality, multi-purpose compost in a deep rootrainer or pot. Sweet peas have very long, straight roots, so it’s important to give them room to stretch. Sow your seeds 2cm deep and gently water them in. Avoid overwatering.
2. Some warmth will help with the germination process so you may need to put your seeds indoors somewhere light to help get them going. As soon as little shoots appear, move them to an unheated greenhouse, cold frame, or porch outside. Your sweet peas will need plenty of light but want to stay cool to slowly develop throughout the winter months.
3. As hardy annuals, sweet peas can tolerate some frost, but you may want to give them some extra protection during hard frosts and prolonged cold snaps. Horticultural fleece is perfect for this – try our Extra Thick Fleece Blanket or the Green Fern Fleece Blanket to keep your plants safe this winter.
4. Keep your sweet peas safe from pests. Mice love to nibble on sweet pea seeds, so wherever you put them for the winter period, make sure it’s mouse-proof!
5. They may well not need watering, but keep an eye on the moisture levels of your plants from time to time to ensure they don't dry out.
6. When temperatures start to rise in early spring, you will need to check the compost more frequently for watering. This is also when we like to start hardening off our plants ready for planting out once the soil is no longer frozen.
7. When to plant your seedlings out depends on your local conditions, but the key is getting them in the ground after the hard frosts have passed.
Should I sow sweet peas in autumn or spring?
The beauty of sowing sweet peas is that you don’t have to choose between autumn or spring sowing – you can do both! Sowing in the autumn can give you stronger, more vigorous plants, but sowing in the spring will also help give you an insurance policy if something happens to your autumn seedlings. Sweet peas sown in spring will germinate quickly in the warmth and will continue to grow on.
Sowing sweet peas in both autumn and spring gives you the best of both worlds, so why wait? Browse our full sweet pea range today!
