Autumn Seed Sowing: Best Sweet Peas to sow in the Autumn

Do you want an early beautiful bloom in your garden?

Sowing sweet peas in the Autumn gives you a head start with stronger plants and earlier flowers. This guide covers it all from preparation to care so your garden thrives.

Key Points

• Sowing sweet peas in autumn gives you stronger plants, earlier flowers and longer flowering than spring sown sweet peas.

• Autumn sowing preparation includes choosing the right soil based compost, using deep containers or cold frames and choosing seeds suitable for autumn sowing.

• Consistent care for young sweet pea plants with regular watering, feeding, support and pinching out tips will give bushier growth and more flowers.

Why Sow Sweet Peas in Autumn?

Sowing sweet peas in autumn is a game changer for any gardener. The main reason is earlier flowers so you can enjoy them sooner in the growing season. Imagine having bright, fragrant flowers in your garden while others are just starting to sprout their spring sown sweet peas.

Autumn sown sweet peas have several advantages over spring sown:

• They become stronger plants that can withstand environmental stresses better.

• The slower growth over winter months means stockier stems and more robust root systems.

• This means longer flowering so you have more time to enjoy the blooms.

Longer stems and bigger, better blooms is a huge bonus so your garden will be a sweet pea haven for sweet pea lovers as they love to grow in these conditions.

Autumn Sowing Preparation

Autumn sowing of sweet peas requires proper preparation. Start by choosing a soil based seed compost which is the perfect medium for sweet pea seeds. Whether you sow direct in the ground or in pots, deep containers are recommended so the roots can grow long and deep.

If you are using cold frames here are some things to consider:

• They should be shallow to promote short jointed growth, about 10 inches at the back and 8 inches at the front.

• Ventilation is key so use wooden blocks to prop open the lights on cold frames.

• During extreme weather cover the whole cold frame with a medium grade polythene sheet and old carpeting as padding material for extra protection during frosty periods.

How to Sow Sweet Pea Seeds in Autumn

Autumn sowing of sweet pea seeds is simple but essential for blooming. Let’s get into the nitty gritty of choosing the right seeds, the sowing process and the germination conditions.

Choosing the Right Seeds

A good garden starts with the right sweet pea seeds. Look for varieties that are suitable for autumn sowing and have a nice fragrance. One such variety is ‘Sweet Pea Air Warden’ with its stunning scarlet-cerise flowers. Fragrance is a big factor so look for varieties labelled ‘highly scented’ or ‘perfumed variety’ such as Sweet Pea High Scent or Sweet Pea King Size, so your garden is filled with lovely scents.

Choosing varieties bred for autumn sowing will make a big difference to your success. These varieties are more tolerant of cooler temperatures and shorter daylight hours so are perfect for autumn planting.

Sweet Pea Air Warden

£1.49

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Air Warden has stunning scarlet - cerise flowers.....

Average Contents : 40 seeds

Sweet Pea Heaven Scent Mixed

£1.49

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Highly scented pastel blooms.....

Average Contents : 40 seeds

Sweet Pea High Scent Seeds - White

£1.49

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High Scent produces white blooms.....

Average Contents : 30 seeds

Sweet Pea King Size Mixed Seeds

£1.49

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Selected for cut flowers.....

Average Packet Contents: 30 seeds

Sweet Pea Mammoth Mixed

£1.49

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Excellent for Cut Flowers.....

Average Contents : 40 seeds

Sweet Pea Spencer Wave Mixed Seeds

£1.49

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Spencer Wave is the standard variety used for garden centre plants.....

Average Contents : 40 seeds

Sowing

Proper timing and technique is key to sowing sweet pea seeds. Here’s how to do it:

1. The recommended sowing time is early October to mid November.

2. Use deep pots like root trainers, about 12-15cm, so the roots can grow long and deep.

3. Fill these pots with peat free, multi purpose potting compost.

4. Sow two seeds per pot, 2-3cm below the compost surface.

Alternatively you can sow one seed to each 7cm (3in) pot or several seeds to a 15cm (6in) pot. Once sown put the pots into a cold frame or greenhouse and cover with newspaper until the seedlings emerge. This will give the seeds the best start in life, protected from the elements and ready to grow strong.

Germination Conditions

Sweet pea seeds need a specific environment to germinate. Keep it cool as overheating can cause poor germination. A little extra heat can help sweet pea seeds germinate in late winter but once they have germinated remove the heat source to prevent tall and leggy growth.

Good drainage is just as important for germination. Don’t waterlog your pots or beds. Make sure your pots or beds have good drainage. This balance of temperature and moisture will help your sweet pea seeds to sprout into healthy seedlings.

Looking after Young Sweet Pea Plants

Once your sweet pea seedlings have emerged their care is paramount. This means regular watering, feeding, support and pinching out tips to encourage bushier growth.

Let’s get into the detail.

Watering and Feeding

Sweet peas need plenty of water. Water thoroughly to avoid stress especially if in pots and during dry weather. Feeding is just as important to grow sweet peas. Start with a high potash fertilizer like tomato food when flower buds appear to promote healthy growth and plenty of blooms. Growing sweet peas is a great addition to your gardening routine so get them in your garden.

Feeding every couple of weeks will make a big difference to the health and vigour of your sweet pea plants. This regular care will ensure your sweet peas will thrive and produce plenty of flowers.

Support

As climbers sweet peas need sturdy vertical support. These can be bamboo canes, trellises or any vertical frame for the plants to scramble up. Most sweet peas can grow up to 2m tall so need robust support structures.

Put supports in immediately after planting and use small twigs to help the young plants. As they grow tie them in every 7-10 days to make sure they are well supported and can grow tall and strong.

Pinching Out Tips

For bushier growth and more flowers, pinch out the tips of your sweet pea plants. When the plants are 10cm tall and have 3 or 4 leaves pinch out the tips. This will encourage side shoots to grow and you’ll have a fuller, stronger plant.

Growers recommend pinching out all the curly stems and tendrils as these can take energy from the flowers and bend the stems. This will ensure your sweet peas put their energy into producing long stemmed blooms.

Overwintering Sweet Peas

To overwinter sweet peas:

1. Protect from frost and give them light.

2. Sweet peas can take -5°C but still need protection from severe frost.

3. Keep them in cold frames, greenhouses or sheltered balconies for winter.

Make sure your sweet pea seedlings get plenty of light and are not below 5°C. Adding extra protection like covering with fleece during frosty weather will keep them safe and healthy through the winter. The hard seed coat of sweet peas also helps with their resilience.

Planting Out in Early Spring

As spring arrives and winter fades your autumn sown sweet peas are ready to be transplanted into the garden. Ideally this should be done at the end of February when the seedlings are 4-5 inches tall with side shoots. Soak the seedlings a few days before planting to make sure they are well hydrated and ready for the move.

When planting spread the roots across a 45 degree angle trench and space the sweet pea plug plants 20cm apart. This will allow the roots to get established in the soil and provide a good base for the plants to grow and thrive.

Common Problems and Solutions

Despite good care sweet peas can have some common problems. These are slugs and mice, leggy growth and mildew. Deal with these as soon as you see them and your sweet peas will be healthy and productive.

Let’s look at the solutions.

Slugs and Mice

Young sweet pea plants can be vulnerable to slugs and mice. To protect them:

• Place slug bait between pots in the cold frame and around transplanted seedlings

• Use beer traps to attract and drown slugs

• Place copper bands around the pots to create a barrier that slugs and snails can’t cross

• Use Nemaslug, a biological control, to target and kill slugs and snails

These will prevent slug and snail damage to your sweet pea plants and protect their seed coat.

For mice occasionally sprinkle paraffin around the outside of the cold frame to repel them. Another method is to place holly around sweet pea seeds to deter mice from digging them up.

Leggy Growth

Leggy growth is often caused by too much heat during germination or not enough light. To prevent this make sure your sweet pea seedlings get light from the start. A cold frame or unheated greenhouse will help keep the cooler temperatures needed for sturdy growth.

If leggy growth occurs you can try to correct it by transplanting the seedlings deeper into the soil, burying part of the elongated stem. This will help the plants develop a stronger root system and stabilise their growth.

Mildew

Under dry or stressful conditions sweet peas can get mildew. Good watering techniques are key to preventing mildew; water them at the base of the plants not the foliage which can encourage mildew to grow. Make sure there is good air circulation around the plants by not overcrowding and pruning excess foliage.

Use natural fungicides like neem oil or baking soda solutions to prevent and treat mildew. Regular monitoring and prompt action will keep your sweet peas healthy and fungus free.

Companion Planting with Sweet Peas

Your garden will be healthier and more productive if you companion plant with sweet peas. Sweet peas are in the pea family and can fix nitrogen in the soil which benefits surrounding plants. They are good companions for nitrogen loving plants like lettuce, kale and other leafy greens.

Planting sweet peas in your garden has many benefits:

• They add beauty with their nectar rich flowers, attract beneficial insects like bees.

• They can create a more balanced and healthy ecosystem.

• But don’t plant onions near sweet peas as they will inhibit nitrogen production.

Harvesting and Enjoying Sweet Peas

To get continuous blooms and prevent seed setting you need to harvest sweet peas regularly. Pick the flowers frequently, ideally when the stems have at least two unopened blooms at the top, to get the longest vase life. This will not only extend the flowering period but keep your plants productive.

Sweet peas are a short lived cut flower, they last 4 to 5 days in a vase. To extend their vase life add sugar or a flower preservative to the water. Deadheading spent flowers will also make your plants focus their energy on producing new blooms not seed pods. Planting earlier flowers like sweet peas will give you more time to enjoy their beauty.

Conclusion

Sowing sweet peas in autumn has many benefits, from earlier flowers and stronger plants to longer flowering. Follow the steps in this guide to prepare your garden, sow your seeds and care for your young plants. Companion planting will help you too.

We hope you enjoyed this guide and will give autumn sowing a go and enjoy growing sweet peas. With a bit of effort and care your garden will be full of colour and scent of these lovely flowers and a true haven of natural beauty.

FAQs

Why sow sweet peas in autumn?

• Sowing sweet peas in autumn means earlier flowers, stronger plants and longer flowering, so you can enjoy them sooner and for longer. Happy gardening!

What compost should I use for sowing sweet pea seeds?

• Use a good quality soil based seed compost like John Innes Seed Compost for sweet pea seeds to grow. This will give them the nutrients and support they need for healthy seedling growth.

How do I prevent leggy growth in sweet pea seedlings?

• Make sure they get enough light and keep them cool.

How do I prevent mildew on sweet peas?

• To prevent mildew on sweet peas use proper watering, good air circulation and natural anti-fungicides. These will work.

How often should I harvest sweet peas?

• Harvest sweet peas regularly to get continuous blooms and prevent seed setting. Pick the flowers when the stems have at least two unopened blooms at the top for the longest vase life.