What to Sow in August to maximise Your Autumn Harvest

August often feels like the tail end of the growing season, but it’s actually an ideal time to sow a new round of crops. With warm soil and milder evenings, many fast-growing vegetables and hardy plants can be started now for harvests later in autumn — or even next spring.

Beds that are clearing out from summer crops offer the perfect opportunity to sow again. Rather than letting space sit empty, it’s worth making the most of the season's final warmth to get one more round of sowing done.

Leafy Greens for Autumn

Asian greens such as pak choi, tatsoi, and mustard are perfect choices for sowing in August. These crops grow quickly in the warm soil and are well-suited to the cooler temperatures that arrive in early autumn. They’re ideal for picking as baby leaves or allowing to grow on into fuller heads.

Hardy lettuces can also be sown now — varieties bred for winter growing tend to perform best. These can be grown in the ground or in containers under cover, offering a steady supply of leaves even as temperatures drop.

Spring cabbages, spring greens, and collards are also well-suited to August sowings. These plants will establish before winter sets in, then continue growing in early spring, giving a reliable crop when little else is ready.

Onions from Seed

For those wanting to try overwintering onions, late summer is a good time to sow varieties bred for that purpose, such as Winteria. These seeds need a little head start while the days are still long and warm, allowing plants to bulk up before entering dormancy. A gentle mulch or fleece can help protect young seedlings from frost later in the year.

Flowers for Next Year

August is also the time to sow biennial flowers that will bloom the following spring and summer. Foxgloves and honesty are two classic choices, but other biennials can be added to the mix for colour, pollinator support, and structure in the garden. Sown now, they’ll produce leafy growth through autumn before flowering next year.

Making the Most of August

When planning what to sow, it helps to look ahead at which crops are about to finish and where gaps will appear in the garden. Using trays or modules can give new plants a head start while space clears, and also offers protection from slugs and pests.

For crops intended to grow into autumn or winter, consider using fleece, cloches, or cold frames to extend the season. Even a small amount of cover can make a significant difference to how long leafy crops continue to grow.

There’s no need to treat August as the wind-down of the gardening year. With the right choices, it can become a second wave of productivity. One that fills the hungry gap between autumn and spring, and keeps the garden ticking along right through winter.