What to Plant in August

Vegetables to Sow, Plant and Harvest in August

August operates on two timelines. The summer garden is at peak production — tomatoes, beans, sweetcorn, and squash are all cropping hard. At the same time, smart gardeners are already sowing the crops that will see them through autumn and winter. Ignore August sowing and you will face bare beds from November onwards. Get it right and you will be harvesting fresh greens well into the new year.

Autumn and Winter Sowing

Overwintering onion sets are one of the best things you can plant in August. Push sets into the soil so the tip just shows, spacing them 10cm apart in rows 30cm apart. These sit through winter, barely growing, then explode into life in spring and give you a harvest in June or July — a full 10-month head start on spring-planted onions. Reliable varieties include Radar, Shakespeare, and Electric Red.

Spinach sown now will give you pickings from October right through to spring. Sow 2.5cm deep in rows 30cm apart and thin seedlings to 15cm. Autumn-sown spinach is less prone to bolting than spring sowings because the days are getting shorter, not longer. It is one of the most reliable winter crops you can grow.

Turnips sown in August will be ready to pull from October to November. Sow thinly in rows 23cm apart and thin to 12cm. Quick-maturing varieties like Atlantic or Tokyo Cross are ideal for August sowing. The roots are tender and sweet when pulled young — nothing like the woody turnips you find in supermarkets.

Winter lettuce is a broad category worth exploring. Lamb's lettuce (corn salad) is incredibly hardy and will crop through the coldest months with minimal protection. Winter purslane and Winter Gem are also reliable. Sow in rows or scatter in blocks. These do not need the heat that summer lettuce demands — they actually prefer cooler conditions.

Pak choi sown in August avoids the flea beetle problems that plague spring sowings. Sow 1cm deep, 30cm apart, and harvest in 6-8 weeks. It bolts quickly in long days, which is why late summer sowing works so much better.

Spring onions sown now will be ready in 8-10 weeks — a fresh supply for autumn salads when the summer crop is finishing. Sow White Lisbon Winter Hardy for the most reliable results.

This is also your last chance to sow spring cabbage. Sow in a seedbed now and transplant to final positions in September, spacing 30cm apart. These will stand through winter and produce heads from March to May next year.

Main Crop Harvest

Tomatoes hit their peak in August. Outdoor tomatoes should be colouring up from mid-month. Pick as soon as the colour starts to turn — they will ripen perfectly on a sunny windowsill and this takes pressure off the plant to produce more fruit. If blight threatens (warm, wet weather), harvest everything green and ripen indoors rather than losing the lot. Remove lower leaves to improve air circulation and reduce disease risk.

Runner beans need checking every 2-3 days. Beans left to grow too large become tough and stringy. Pick when they are 15-20cm long and snap cleanly. Regular picking encourages the plant to keep producing. A well-picked plant will crop until the first frosts in October.

Sweetcorn is ready when the tassels turn brown and dry. Test by pushing your thumbnail into a kernel: if the liquid is milky, it is ready; if watery, wait a few more days; if doughy, you have left it too late. Cook within hours of picking — the sugars start converting to starch immediately after harvest.

Maincrop potatoes should be lifted this month before slug damage sets in. Choose a dry day, fork them out carefully, and leave on the soil surface for an hour to dry the skins. Store in paper sacks (not plastic) in a cool, dark place. Check regularly and remove any that show signs of rot.

Cucumbers and courgettes are still producing heavily. Keep picking courgettes while they are small (15-20cm) — leave them too long and they turn into watery marrows. Beetroot is best pulled when golf-ball to tennis-ball sized. French beans — pick regularly to extend the harvest for several more weeks.

Seed Collecting and Saving

August is the start of seed-saving season, and it is one of the most rewarding things you can do as a gardener. By saving seed from your best-performing plants, you build up varieties uniquely suited to your soil, climate, and growing conditions — and it saves money year after year.

Let the best tomatoes over-ripen on the plant, scoop out the seeds, ferment them in a jar of water for 2-3 days (this removes the germination-inhibiting gel), then rinse and dry on kitchen paper for 2 weeks. Store in labelled paper envelopes in a cool, dry place.

Runner beans and French beans — leave a few pods on the plant until they dry out and rattle. Shell them and spread the seeds on kitchen paper to dry for 2 weeks before storing. Peas work the same way. These are some of the easiest seeds to save.

Calendula, sweet peas, nigella, and poppies all produce seed that is easy to collect. Wait until the seed heads are dry and papery, then shake into a paper bag. Label everything clearly with the variety name and date.

Quick Wins for August

• Radishes (autumn varieties) — varieties like China Rose and Black Spanish are perfect for August sowing. Ready in 6-8 weeks, much hardier than summer types.
• Pak choi — sow now for harvest in just 6 weeks. Better in late summer than spring because flea beetles are less active.
• Lamb's lettuce — sow for picking from October onwards, lasting well into winter. Ready in about 8 weeks.
• Spring onions — a quick crop from August sowing, ready in 8-10 weeks for autumn salads.
• Last courgettes — if you missed sowing earlier, you can still plant out young courgette plants for a late crop before the frosts arrive.

Flowers in August

August is a transitional month in the flower garden. Summer borders are still at their peak, but the smart gardener is already thinking about spring. Bulb planting begins, seed saving is in full swing, and deadheading keeps the colour going for as long as possible.

Plant Spring-Flowering Bulbs

Late August marks the start of the bulb planting season, and getting daffodils and narcissi in early gives them the longest possible time to establish roots before winter. The earlier you plant, the better the display next spring. Plant at a depth of 2-3 times the bulb's height — for most daffodils, that means about 10-15cm deep, spaced 10cm apart.

Crocuses can also go in from late August, planted 8cm deep in groups of 10 or more for the best effect. Alliums should be planted now too — the large-headed varieties like Purple Sensation need deep planting (15cm) and look spectacular in borders. Tulips are the exception: wait until November to plant these, as early planting increases the risk of tulip fire disease.

Collect Seeds and Take Cuttings

Collect ripe seeds from calendula, sweet peas, nigella, and poppies. Wait until the seed heads are dry and papery, then shake them into a paper bag or envelope. Label clearly with the variety and date. Stored in a cool, dry place, most flower seeds remain viable for 2-3 years.

Take semi-ripe cuttings from lavender, rosemary, sage, and other woody herbs. Cut 10cm shoots of this year's growth, strip the lower leaves, dip in rooting hormone if you have it, and push into a mix of sharp sand and compost. These root easily in a sheltered spot and will be ready to plant out next spring.

Keep Deadheading

Dahlias, roses, sweet peas, and cosmos will all keep flowering well into autumn if deadheaded regularly. Cut sweet peas every 2-3 days — if you allow seed pods to form, the plant stops producing flowers. Feed roses with a potash-rich fertiliser after the second flush of flowers to encourage a strong third flush in September. Dahlias respond to regular feeding and deadheading with ever-larger blooms right up to the first frost.

Fruit in August

August is one of the best months for fruit in the UK garden. Early apples, plums, and soft fruit are all ripening, and there is plenty to do to prepare for next year's crop.

Early apple varieties like Discovery and Worcester Pearmain ripen from mid-August. Pick when the apple twists off the branch easily with a gentle upward turn — if you have to tug, it is not ready. Early apples do not store well, so eat them fresh or cook within a couple of weeks.

Plums and damsons are ready this month. Pick before the wasps get to them — check trees daily once the fruit starts to soften. Plums are excellent for jam, crumbles, and freezing. Damsons make outstanding gin and preserves. If you have a heavy crop, freeze the surplus immediately.

Autumn raspberries start cropping from August onwards. These fruit on the current year's canes (unlike summer varieties which fruit on last year's growth), so they are cut to the ground in winter. Pick every few days for the freshest fruit. Varieties like Autumn Bliss and Polka are heavy croppers.

Blackberries ripen throughout August. Pick when fully black and glossy — if they are still slightly red, they will be sour. Blackberries freeze brilliantly: spread them on a tray, freeze until solid, then transfer to bags. Perfect for crumbles and smoothies all winter.

Strawberries — the main crop is finished, but now is the time to prepare for next year. Remove old, tired foliage and peg down runners to create new plants. Once rooted, these runners can be separated from the parent plant and transplanted to a new bed in September. Use our mulch calculator to work out how much bark mulch you need for the new strawberry bed.

Regional Planting Adjustments

August is a generous month across the UK, but the window for autumn sowing is shorter the further north you go. Act promptly if you want winter crops to establish before the cold sets in.

The key message for August: do not assume the growing season is ending. There is still time to sow a wide range of crops for autumn and winter harvest — but you need to act now, not in September when the soil starts cooling and daylight hours shorten rapidly.

Common August Planting Mistakes

1. Stopping sowing too early. Many gardeners think August means the season is ending. Wrong. Spinach, turnips, winter lettuce, and overwintering onions all need to be sown NOW for autumn and winter crops. The garden does not stop producing just because summer is winding down.
2. Not preparing ground for autumn planting. Clear spent crops as soon as they finish, add a generous layer of well-rotted compost, and mulch bare soil. Empty beds left bare lose nutrients and structure to rain and weeds. Use our compost calculator to work out how much you need.
3. Letting crops over-ripen on the plant. Overripe courgettes become watery marrows. Old beans go tough and stringy. Runner beans left too long signal the plant to stop producing. Harvest little and often for the best quality and continued production throughout the month.
4. Neglecting lawn care in heat. August lawns need water during drought spells but should not be cut too short. Raise your mower height to 4cm minimum — longer grass shades the roots, retains moisture, and stays greener. Use our lawn feed calculator if you are feeding this month.
5. Forgetting to order garlic and onion sets for autumn. Popular varieties sell out by September. Order now for October and November planting. Good garlic suppliers include the Garlic Farm (Isle of Wight) and specialist seed companies. The earlier you order, the better the selection.

Frequently Asked Questions

Where to Buy Seeds and Plants in the UK

Ready to plant? These UK suppliers stock everything you need for August sowing, autumn preparation, and spring bulbs.

Links marked above are affiliate links — we may earn a small commission at no extra cost to you. We only link to reputable UK suppliers.

Useful Gardening Tools

Planning your August planting? These free calculators help you work out exactly how much you need.