Late summer flowers like asters, rudbeckia and tithonia really come into their own in August, and veg plots are filled with an abundance of food. As well as enjoying the garden in all its splendour, it’s an ideal time to plan ahead. Vegetables and herbs sown now will establish quickly, providing welcome harvests through autumn and into winter. Hardy annuals can be sown outside from the end of the month.

What to Sow in August – at a glance:

Vegetables: lettuce, spinach, Oriental leaves, wild rocket, corn salad, spring onions, turnips, chicory, cabbages, chard, Japanese onions, kohlrabi, radish, sorrel, fennel, pak choi, endive, radicchio, pea shoots, winter radish, amaranth, kale, winter purslane, American land cress

Herbs: parsley, coriander, chervil, sorrel

Flowers: calendula, forget-me-not, wild carrot, Californian poppy, cornflower, green manure

Vegetables and Herbs

Pak choi

Pak choi is a great crop for shady spots

This quick-growing member of the Brassica family adds a delicious crunch to salads, soups and curries. Late summer sowings are less prone to bolting and can be sown directly into vegetable beds and borders. Baby leaves are ready to be picked within a month. For larger leaves, protect late summer sowings with fleece or a cloche and you’ll be rewarded with harvests up until the end of autumn.

Sow seeds in fertile, moist-retentive soil in partial shade, at a depth of 2cm. Thin seedlings to 10cm apart for baby leaves and 30cm for mature plants. Slugs have a particular fondness for pak choi and I find they munch on the emerging seedlings before they can get established. If this is the case in your garden, sow seeds in modules filled with peat-free compost and keep seedlings well-watered to avoid bolting. Plant out when around 5cm tall.

Many pak choi varieties are highly ornamental like ‘Red Choi’, with its bright green stems and deep purple leaves. Green-stemmed types, such as ‘Green Revolution’ (a bolt-resistant variety that’s great to grow in containers) are ideal for baby leaves and white-stemmed pak choi like ‘Hanakan’ is vigorous and quick to produce mature heads of leaf.

Kale

Sow kale seeds early in the month

One of the joys of the winter veg garden, kale provides a delicious harvest of greens right through to early spring. It’s not too late to sow now, but get seeds in as soon as you can this month. If you have room you can sow in situ, but kale is often started off in a seedbed and transferred to its final position once summer crops have been harvested.

Sow 2cm deep in a rich, well-drained soil, with rows spaced 45cm apart. Thin to 60cm or plant out in final positions 6-8 weeks after sowing, firming soil well around the seedlings as you transplant to avoid wind-rock. Seed can also be started off in modules in peat-free seed compost. There are many fantastic varieties to try like the compact purple-stemmed ‘Curly Scarlet’, the eye-catching ruby leaves of ‘Redbor’ and my personal favourite – elegant ‘Cavolo Nero’.

For super-sustainable pickings, you could try growing perennial kale from cuttings. Once you’ve established an old heritage variety like Daubenton kale or Taunton Deane kale, you’ll have winter greens without the need to resow each summer.

Winter purslane

Winter purslane is great for quick salad crops

The succulent, heart-shaped leaves of this low maintenance salad crop, along with the tiny white or pink flowers at their centres, can be used for cut-and-come-again pickings during the lean months when other salad greens have succumbed to the chilly winter weather. Winter purslane is best sown in late summer for harvesting throughout autumn and winter.

Seeds can be sown direct this month in a sunny spot, 1cm deep in well-prepared soil and should germinate quickly. Thin seedlings to 25cm apart (thinnings can be used as baby leaves) and within 12 weeks you should be able to start harvesting. Winter purslane will self-sow freely, but seedlings are easily removed so it shouldn’t become a nuisance.

Also known as miners’ lettuce, this native of North and Central America is packed full of vitamin C (as well as Vitamin A and iron). It was eaten in the Californian Gold Rush, by miners, to ward off scurvy. Leaves can be used raw in salads or cooked like spinach.

Coriander

Sowing coriander now will help prevent plants bolting

Coriander can still be sown outdoors during August and into September. Make small sowings in well-drained soil every couple of weeks to ensure a steady supply into autumn. Thin plants to 25cm apart and keep soil moist to prevent bolting.

Plants maturing over the next couple of months should be more bolt-resistant than those growing earlier in the season, as cooler temperatures make it less likely that plants will flower prematurely. If your coriander does bolt, you can leave it and collect the ripe seed to use in the kitchen or sow next year.

If, like me, you struggle to harvest coriander earlier in the summer without it bolting, you could try growing Vietnamese coriander (Persicaria odorata), the young leaves of which have a strong coriander taste. This tender perennial prefers moisture-retentive, well-drained soil in a sunny spot.  It can be overwintered in a container indoors. I grow it as a backup for those times when my annual coriander starts to bolt. Alternatively, choose bolt-resistant varieties like ‘Leisure’ and ‘Slow Bolt’.

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Chervil

Protect chervil sowings with cloches as temperatures drop

This delicately aniseed-flavoured herb, valued by the Romans for its medicinal properties, is one of the key ingredients of the classic French seasoning fines herbes, with parsley, tarragon and chives. Mrs Beeton’s Book of Household Management describes chervil as a flavouring of entrées, sauces and soups, and the famous Victorian cookbook also recommends this dainty herb as a decorative garnish for savoury dishes and salads.

Initial sowings in early to mid-spring for summer harvest can be followed by repeat sowings this month for use in autumn and winter. Plants for winter cropping are best protected with cloches or grown in a greenhouse or cold frame. Sow seeds in a semi-shady spot in moisture-retentive soil and thin seedlings to 15cm apart. Chervil is ideal for containers and window boxes, providing they are at least 15cm deep to accommodate the long tap root. Sow thinly in nutrient-rich, peat-free compost and cover lightly. Germination takes around two to three weeks.

Like coriander, chervil is prone to bolting in hot weather, so it’s important to keep plants well-watered, especially if they’re planted in containers.

Thrifty tip

Garden centres often sell seeds at reduced prices at the end of summer, making it easy to stock up on bargains ready for next year. Choose seeds that keep well and check the dates on the packet before you buy. Tomato, pea, beans, pepper, chilli, squash, cucumber and brassica seeds should all store for several years and most seed packets contain more seeds than you need, so if you buy with friends, you can save money and broaden the range of plants you grow.

Flowers

Calendula

Pick a sunny spot to grow pot marigold

As we approach the end of the month, it’s time to start sowing hardy annuals like calendula, also known as pot marigold. If you’ve grown these cheerful, versatile blooms before, your plants may well have done the work for you and self-seeded enthusiastically throughout the borders. If not, it couldn’t be easier. Simply scatter the curly seeds in situ in a sunny spot along the edges of vegetable beds to encourage pollinators to visit, add to the front of herbaceous borders or sow in pots for a vibrant display next summer.

For a hit of fiery colour try ‘Neon’ and ‘Indian Prince’; then cool off with the elegant semi-double ivory flowers of ‘Snow Princess’. She’s a hardy soul and overwinters well in my garden, especially in containers. Perhaps my favourite varieties (though it’s so hard to choose) are coppery calendulas like ‘Sherbet Fizz’ and ‘Sunset Buff’.

Green manure

Sow green manures now to protect bare patches of ground

If you have areas that will be left empty over winter, why not sow a green manure to protect the soil and prevent nutrients being washed away? There are a range of green manures to suit different soil types and times of year. Grazing rye is ideal to improve clay soils, although it can be grown on most soils, as a winter green manure. Sow seed now and dig in next spring.

Winter tares and winter field beans are also suitable to leave until next spring. Both fix nitrogen, which helps to improve the fertility of the soil. Field beans are excellent to break up heavy soils and winter tares or ‘Vetch’ protects well against weeds, but dislikes acid or dry soils.

Field beans and tares are in the Fabaceae family, so it’s important to avoid growing other vegetables like peas or beans in the same ground next year. As part of a standard crop rotation system, legumes would normally be followed by brassicas, so these areas would be perfect for crops like cabbages, turnips and Brussels sprouts.

Growing Greener

Water-wise gardening is more important than ever this month. Water butts are key to conserving any summer rain – a vital source of water for thirsty plants like seedlings. If you’re going on holiday, make sure plants don’t dry out while you’re away. Pass any seedlings in modules and small pots on to family or friends to water until you get back, or use trays covered with capillary matting above a reservoir of water to keep compost moist for a few days. Make sure you add a strip of matting as a wick to draw water up from the tray to the base of the pots.