By the time August arrives, the allotment has usually stopped feeling like a race. The beans are climbing, the courgettes are out of control, and most of the spring panic about getting things in on time has passed. So a lot of people assume the sowing is over. It isn’t, not by a long way. August is one of my favourite months for putting seed in the ground precisely because the pressure is off and the soil is warm. The trick is that you stop sowing for summer and start sowing for autumn, winter, and next spring instead.
Here in Oxfordshire I treat the second half of summer as a quiet second season. Beds that have given up their broad beans or early potatoes don’t need to sit bare until next year. There’s a surprising amount that will still germinate, grow, and crop before or through the colder months, and a few things that want sowing now precisely because they need the long, slow start. Below is what I actually sow in August on my own plot, why, and the bits that catch beginners out.
What August Sowing Is Really For
The mental shift that helps is this. In April and May you sow for the summer plate. In August you sow for three different timelines at once: fast crops to fill the gap right now, hardy crops to carry you through autumn and into winter, and a handful of things that want sowing in late summer so they’re well established before the cold arrives. Once you think in those three buckets, the whole month makes sense.
Warm soil is the great advantage. Seeds that sulked in a cold April seedbed will be up in days now. The thing working against you is dryness, because August beds can bake hard, so watering the drill before you sow matters far more than it did in spring. I’ll come back to that, because it’s the single biggest reason late-summer sowings fail.
Salad Leaves You Can Keep Sowing
Salad is the easiest win in August and the one I’d start with if you only do one thing. Lettuce sown now crops into autumn, and because the worst of the summer heat is passing, it’s far less likely to bolt than the batches you sowed in June. I sow a short row of loose-leaf lettuce like ‘Salad Bowl’ or ‘Lollo Rossa’ every couple of weeks so there’s always something to cut rather than a glut all at once.
Rocket comes into its own now too. It bolts almost on sight in high summer, but an August sowing in cooler conditions stays leafy and useful for weeks. The same goes for mizuna, mustard leaves, and the looser oriental salad mixes. These are cut-and-come-again crops, so one sowing keeps giving. If you want a proper steer on successional salad timing, the Royal Horticultural Society has a clear guide to sowing salad leaves through the season at the RHS salad leaves page.
Fast Crops: Radishes, Spring Onions and Turnips
If a bed has just come empty and you want it earning its keep again quickly, this is the group to reach for. Radishes are the fastest thing in the vegetable garden and will be ready in three to four weeks from an August sowing, which means you can squeeze a full crop in before the season turns. Sow them thinly, because crowded radishes go to leaf and never bulk up properly, a mistake I made for years before I learned to thin without sentiment.
Spring onions sown now will stand into autumn and some varieties, like ‘White Lisbon Winter Hardy’, will overwinter for an early pull next year. Turnips are the underrated one here. An August sowing of a quick variety such as ‘Snowball’ gives you tender, golf-ball-sized roots in autumn that taste nothing like the woody supermarket version. They want consistent moisture, but they’re genuinely fast and forgiving.
Oriental Leaves and Pak Choi
Pak choi is one of those crops that almost demands to be sown late. Sow it in spring or early summer and it bolts the moment it gets warm and stressed, which is maddening when you’ve watched it grow nicely for a fortnight. Sow it in August into cooling conditions and it behaves itself, forming proper plump heads. The same is true of choi sum, tatsoi, and Chinese cabbage.
These oriental brassicas are quick, they’re happy in a bit of shade if your August beds are still catching strong sun, and they shrug off the cooler nights that are coming. Watch for flea beetle, which peppers the leaves with tiny holes. A layer of fine mesh over the row early on is the simplest defence and saves a lot of nibbled, lacy leaves.
Spinach and Chard for the Cooler Months
True spinach is a cool-season crop at heart, which is exactly why August suits it. A sowing now establishes through autumn and, with a bit of protection, will give you pickings well into winter and a flush again in early spring. Sow a variety described as hardy or for autumn use, water the drill well, and keep it picked over rather than letting the leaves get large and bitter.
If you’ve never had luck with spinach bolting on you in summer, an August sowing is the answer. Perpetual spinach and chard are even more reliable and tougher through cold weather. Chard in particular is one of the most generous things you can grow over winter, standing through frost on my clay and cropping when little else will. One late-summer sowing of chard genuinely earns its space for the best part of a year.
Spring Cabbage and Crops to Overwinter
This is the part of August sowing that beginners most often miss, and it’s the one with the longest payoff. Spring cabbage is sown now, in late summer, to grow into small plants before winter, sit through the cold, and then romp away to give you fresh greens in the hungry gap of March and April when almost nothing else is ready. Sow into a seedbed or modules in August, transplant in autumn, and you’ll be cutting tender spring greens when the shops are still selling tired imports.
It’s the same logic as autumn-planted garlic, which goes in soon after this and overwinters in the same way. If you haven’t grown garlic before, it’s one of the easiest overwintering crops there is, and I’ve written up the whole process in my guide to how to grow garlic in the UK. Lamb’s lettuce, also called corn salad, and land cress are two more hardy salads worth sowing now for winter cutting, both of which laugh at frost.
Herbs That Still Have Time
Coriander is the obvious one. Like rocket and pak choi, it bolts in the heat of summer and runs to seed before you’ve had a decent picking. August’s cooler nights are exactly what it wants, so a late-summer sowing gives you the longest run of leaf you’ll get all year. Sow it where it’s to grow rather than transplanting, because it hates root disturbance, and keep it cut. There’s more detail on getting it right in my full guide to growing coriander in the UK.
Parsley sown now will establish before winter and stand for fresh picking through the cold months and into a second year. Dill and chervil are both happy with an August start too. These are the herbs that actually prefer the shoulder of the season rather than high summer, so don’t write them off just because the main herb-sowing window feels like it’s behind you.
Green Manures for Beds You Have Cleared
If a bed comes empty and you’ve nothing to sow into it, don’t leave bare soil to bake and wash away over autumn. Sow a green manure instead. These are fast-growing cover crops you sow to protect and improve the soil, then dig in or cut down before they flower. Mustard is the quickest and germinates almost overnight in warm August ground. Phacelia is my favourite for late summer because it’s pretty enough that the bees find it before you turn it in.
Field beans and grazing rye can also go in a little later and will hold the soil right through winter. The point of all of them is the same: keep the ground covered, feed the soil structure, and smother weeds while a bed would otherwise be idle. Garden Organic has a thorough rundown of which green manure suits which situation at their green manures guide, and it’s worth a read if you’ve never used them.
Hardy Annuals and Sweet Peas for Next Year
It’s not all vegetables. Some of the best hardy annual flowers actually want sowing in late summer or early autumn rather than spring, because the young plants overwinter as sturdy little clumps and then flower weeks earlier and far bigger than anything you sow next March. Calendula, cornflowers, larkspur, poppies, and ammi all respond brilliantly to an autumn start. I scatter them into a corner of the veg beds and barely think about them again until they put on a show.
Sweet peas are the standout. Sown in late August or September and overwintered in a cold frame or unheated greenhouse, they build a strong root system and reward you with earlier, more abundant flowers than a spring sowing ever will. If you only try one autumn-sown flower, make it sweet peas. The team at BBC Gardeners’ World explain the autumn sowing approach well in their guide to sowing sweet peas.
Getting Seeds to Germinate in Late Summer Heat
Here’s the bit that decides whether any of this works. August soil dries out fast and bakes into a crust that seedlings struggle to push through. The fix is simple and I do it without fail now. Draw out your drill, water along the bottom of it generously, let it soak in, then sow into the damp and cover with dry soil. The seed sits in moisture while the dry cap on top stops the surface crusting. It feels back to front the first time you do it, but it transforms your strike rate.
Keep things shaded for the first few days if the sun is fierce. A length of fleece, a plank laid over the row until you see the first shoots, or simply sowing in the cooler part of the day all help. And keep the watering steady, because the most common reason an August sowing fails isn’t cold or pests, it’s a row that germinated and then dried out the moment you looked away. If you want a refresher on the basics of getting seed up reliably, my guide to growing vegetables from seed in the UK covers it from the start.
Common Questions About Sowing in August
What can I sow in August in the UK?
You can sow a surprising amount in August. Fast crops include salad leaves, radishes, turnips and spring onions. Hardy crops for autumn and winter include spinach, chard, pak choi and oriental leaves. Late summer is also the time to sow spring cabbage and overwintering salads, along with hardy annual flowers and sweet peas for an early display next year.
Is it too late to sow vegetables in August?
Not at all. August is too late for most summer crops like beans, courgettes and tomatoes, but it’s an excellent month for fast crops such as salad leaves, radishes and turnips, and for hardy crops like spinach, chard and spring cabbage that carry you through autumn and winter. The warm soil means seeds germinate quickly.
What is the easiest thing to sow in August?
Salad leaves and radishes are the easiest. Both germinate fast in warm soil, need very little fuss, and crop within a few weeks. Loose-leaf lettuce, rocket and oriental salad mixes are all far less likely to bolt now than in high summer, so they’re more reliable than earlier sowings.
Can I sow spinach in August in the UK?
Yes, and August is one of the best times to do it. Spinach is a cool-season crop that bolts in summer heat, so a late-summer sowing establishes as conditions cool and gives you pickings through autumn and, with some protection, into winter and early spring. Choose a variety described as hardy or for autumn use.
When should I sow spring cabbage?
Late summer, roughly from early August to early September in most of the UK. Sown now, spring cabbage grows into small plants before winter, sits through the cold, and then puts on rapid growth to give you fresh greens in March and April, when little else is ready. Transplant the young plants to their final spacing in autumn.
What flowers can I sow in August?
Hardy annuals such as calendula, cornflowers, larkspur, poppies and ammi all do well from a late-summer or early-autumn sowing, overwintering as young plants and flowering earlier and bigger next year. Sweet peas are the standout, sown in late August or September and overwintered for a strong, early display.
Why do my August sowings keep failing?
The usual culprit is dry soil. August beds bake hard and crust over, so seeds either fail to germinate or dry out just after they do. Water the bottom of the drill before sowing, sow into the damp, cover with dry soil, and keep the row consistently moist and lightly shaded until the seedlings are up.
A Sensible Place to Start
If August feels like a lot of options, narrow it right down. Sow a row of salad leaves and a row of radishes this week for something quick, get spinach or chard in for the colder months ahead, and start a tray of spring cabbage for that early greens crop next year. That’s three sowings covering all three timelines, and it’s plenty to be getting on with.
From there, build out as beds clear. For a quick visual of when every crop wants sowing and harvesting across the year, keep my UK Vegetable Planting Calendar handy. This sits naturally alongside the previous month, so it’s worth a glance back at what to sow in July to see what still has time, while how to grow spinach in the UK and when to plant cabbage in the UK cover two of the best August sowings in full.