Seeds to Sow in Autumn. The best UK seeds for September and October.
If you are anything like me (a summer-born baby, avid gardener, and at my happiest in the summer months) you’ll walk into September mourning the loss of summer and the loss of the garden, somewhere you’ve spent most of your time in for the last 5 months.
But it doesn’t have to be this way. September and October can be very busy in the garden, and there’s a lot to do other than harvesting the last of the summer crops. There is in fact still some planning and seed sowing you can be doing while the weather is still warm enough. Some of these crops will feed you through the darkest months and some with get you off the starting line early come spring.
Seeds to sow in September and October. Autumn sown crops for winter and early spring.
1. Sweet peas
2. Winter lettuce
3. Swiss or rainbow chard
4. Onions
Sowing Sweet peas in autumn/fall
Sweetpeas (Lathyrus odoratus) are typically sown in late winter or early spring in most regions, however, in climates with milder winters it is a good idea to sow them in autumn to give them a head start. This should give you stronger plants and earlier blooms come spring.
Benefits of sowing sweet peas in autumn
1. Early blooms: By sowing sweet peas in the autumn, you can expect earlier blooms compared to spring-sown varieties. Autumn-sown sweet peas tend to flower in late winter or early spring, providing much-needed colour and fragrance during a time when many other plants are dormant or just starting out.
2. Extended growing season: Because your autumn-sown sweet peas bloom in early spring you can then sow another set of sweet peas to enjoy in summer too. Giving you many more months of sweet-smelling flowers by the kitchen sink.
3. Stronger plants: Sweet pea plants sown in the autumn have more time to establish strong root systems before the hot and dry conditions of summer. This can result in healthier and more robust plants that are better equipped to handle the stresses of the growing season.
4. Less chance of heat stress: Spring-sown sweet peas can sometimes struggle with heat stress and may stop flowering as the weather warms up. Autumn-sown varieties are less likely to experience this issue, as they bloom before the onset of hot weather.
5. Less pest problems: Some pests that affect sweet peas, such as aphids and powdery mildew, are more common in the warmer months. By sowing sweet peas in the autumn, you can avoid the peak of these pest problems.
6. Less to sow in spring: I don’t have a huge amount of space indoors to start seedlings off in later winter/early spring. So if there are any I can start in autumn to get ahead of the game a free up space for other seedlings come spring the better.
It's important to note that the success of autumn-sown sweet peas depends on your specific climate and local growing conditions. Sweet peas are cold-tolerant, but they may not thrive in extremely cold or harsh winter climates. Be sure to choose varieties suitable for your region and provide appropriate care and protection, keeping them in a greenhouse until you are ready to plant them out in the spring.
Guide on how to sow sweet peas in autumn
1. Seed Soaking (Optional): Some gardeners soak sweet pea seeds in water for a few hours or overnight before planting to help with germination. This step is optional but can be beneficial.
2. Sowing: 9 inch pots work well for sowing sweet peas. Plant about 1 inch deep. You should be able to fit 3 seeds in each pot, spacing evenly. Cover the seeds with soil and gently pat down the soil to ensure good seed-to-soil contact. You can plant all three seedlings out together in spring, don’t worry about dividing them up.
3. Watering: You won’t need to water too often as the colder months will mean the soil stays moist for longer. Keep an eye on your seedlings and think moist not wet. This is what they will thrive in.
4. Pinch out: Once your seedlings have grown their true leaves (see picture below) you can pinch out these leaves (the top two leaves, leaving just two behind). This will encourage the plant to grow brushier and provide you with more blooms.
5. Plant out in spring: In early spring, as temperatures rise and the risk of frost diminishes, you’ll be able to plant your seedlings in the ground. Your sweet pea seedlings should then begin to grow more vigorously. Water in well and then they should need very little water from here on in if your planting into healthy no-dig soil. If they look like they are struggling you can give them a drink. Read “how to water less with no-dig gardening.”
6. Provide support: Your sweet peas will need something to grow up like a trellis or bamboo sticks. You can get creative with this.
Remember that sweet peas prefer cool temperatures, so if you live in a region with very hot summers, be prepared for the possibility that they may stop flowering as the weather gets warmer. In such cases, you can cut them back and encourage a second flush of blooms.
Also, remember sweet peas are a cut and come again crop. Meaning the more you pick the more you encourage the plant to flower. So pick as many as you can, fill your home with blooms, and take a bunch to all your friends.
2. Winter Lettuce
There are severall lettuce varieties well suited to the cooler UK climate that can be sown in autumn and harvested throughout winter. Look for lettuce varieties that are known for their cold tolerance and slower bolting (going to seed) tendencies.
10 Best Lettuce varieties for autumn sowing in the UK:
1. Winter Density: This is a popular choice for autumn planting in the UK. Winter Density forms compact, dense heads with crisp, sweet leaves. It is known for its cold tolerance and can withstand cool, damp conditions.
2. Arctic King: As the name suggests, Arctic King is well-suited for cold climates. It's a butterhead lettuce with tender leaves and good resistance to bolting. It's an excellent choice for autumn and early winter harvests.
3. Rouge d’Hiver: This French heirloom variety is a loose-leaf lettuce with red-tinged leaves and a rich, buttery flavor. It's known for its cold resistance and is suitable for autumn planting.
4. Valdor: Valdor is a crisphead or iceberg lettuce variety that holds up well in cooler weather. It forms tight, compact heads with crunchy leaves and a mild flavour.
5. Winter Marvel: Winter Marvel is a reliable winter lettuce that can be sown in autumn. It produces dense, green heads with a crisp texture and a sweet taste.
6. Four Seasons: This butterhead lettuce is known for its versatility. It can be sown in autumn and harvested in late autumn or early winter. It has attractive red-tinged outer leaves and tender, buttery inner leaves.
7. Little Gem: Little Gem is a compact, mini-cos lettuce variety that is well-suited for autumn planting. It forms small, dense heads with sweet, crisp leaves.
8. Winter Gem: Winter Gem is a variation of Little Gem specifically bred for winter hardiness. It produces small, compact heads with good cold resistance.
9. Red Salad Bowl: This loose-leaf lettuce variety has attractive red-tinged leaves and is suitable for autumn planting. It's known for its mild flavor and tolerance to cool temperatures.
10. Winter Butterhead: As the name suggests, this lettuce is a butterhead variety well-suited for winter growing. It forms loose heads with tender, buttery leaves.
All of these varieties can be planted outside over winter in milder climates, though it is a good idea to mulch around them or add a fleece layer to protect from frost. Alternatively, if you have the space plant them in a greenhouse or under a cold frame over winter.
3. Winter cropping Swiss chard
Swiss chard, rainbow chard or perpetual spinach can all be grown over winter in the UK and other mild climates. Chard can tolerate cooler temperates and light frosts making it a good seed to sow in the autumn. It can then be planted outside or under cover in a greenhouse or cold frame.
A Guide to planting chard and spinach over winter.
1. The right location: Select a location in your garden that receives at least partial sunlight. Swiss chard can tolerate some shade but prefers full sun to partial shade.
2. Adopt no dig principle: Swiss chard grows well in well-draining, fertile soil. Amend the soil with compost or well-rotted organic matter to improve its fertility and structure. Mulching the plants will also help to protect the roots from frost.
3. You can sow chard directly in the ground in later summer or in modules: For later autumn sowing modules work better to start off the seedlings in a greenhouse or on a window sill for better germination rates.
Once the seedlings are strong enough you can plant them outside or in the ground in a greenhouse.
4. Watering: Keep seeds moist but not wet. They will need much less water than in the summer months. Once planted out you will not need to water them.
5. Thin the seedlings: Once the Swiss chard seedlings have sprouted and have a couple of true leaves (usually a few weeks after planting), thin them to maintain proper spacing. Leave the healthiest and strongest seedlings and remove the extras.
6. Harvesting: Swiss chard leaves can be harvested when they reach the desired size, typically around 6 to 8 inches in length. You can harvest the outer leaves while leaving the inner ones to continue growing.
7. Protect from frost: If you expect frost in your area, consider using row covers or cloths to protect the Swiss chard plants and extend the growing season.
4. Onions to sow in autumn.
Onions can be sown in the autumn as well as early spring. For late summer and autumn sowing it is best to use short-day varieties of onions. This allows the seeds to establish strong root systems before winter and early bulb formation in spring.
A guide to sowing onion seeds in autumn/fall
Start onion seeds indoors in seed trays or containers with well-draining potting mix.
Sow the seeds in modules 8-9 seeds in each module. Then cover them with a thin layer of potting mix.
Keep the soil consistently moist but not waterlogged.
Maintain a temperature between 18°C to 24°C (65°F to 75°F) for germination.
Transplant onion seedlings into the garden when they have grown to about 6 inches tall. You can transplant the whole module of hopefully 8-9 seedlings out together. You do not need to separate them.
Once the onions are the size of spring onions thin them out leaving 3-4 in the ground. You can use the thinning as spring onions in salads etc.
The onions left in the ground will start to bulb up in spring and happily grow together pushing themselves apart. This is a good way of growing more onions in one space.
The best short-day onion varieties for autumn sowing in the UK:
1. Struon: Sturon is a popular short-day onion variety in the UK. It produces medium to large-sized bulbs with a mild, sweet flavour. It's known for its excellent storage qualities, making it a great choice for storing over the winter months.
2. Electric: Electric is another short-day onion variety that performs well in the UK climate. It produces medium-sized, globe-shaped bulbs with a mild and sweet taste. These onions are ideal for both fresh use and storage.
3. Centurion: Centurion is a short-day onion variety known for its reliability and adaptability to the UK climate. It produces medium-sized bulbs with a strong flavour, making it suitable for cooking and salads.
4. Setton: Setton is a short-day onion with good disease resistance and a mild, sweet flavor. It produces large, round bulbs that are excellent for storage. Setton onions are also known for their uniform shape and size.
5. Turbo: Turbo is a short-day onion variety that produces early, round bulbs with a mild taste. It's often chosen for its ability to mature quickly, making it a good choice for early harvesting.
6. Senshyu Yellow: Although Senshyu is traditionally grown as a Japanese variety, it performs well in the UK. It's a short-day onion known for its yellow skin and mild flavor. Senshyu onions are typically harvested in late summer.
7. Fen Globe: Fen Globe is a short-day onion variety that is well-suited for cooler climates like the UK. It produces round to slightly flattened bulbs with a mild flavor, making it suitable for a wide range of culinary uses.
8. Walla Walla: Walla Walla is a fantastic old French variety producing one of the sweetest onions available. Autumn sown Walla Walla grow much bigger than spring sown. A short keeper so use fresh from the ground rather than storing.