Seeds to Sow in Summer

If you’re alarmed by the speed at which summer seems to be racing by, please don’t fret – there’s still plenty of time to sow all sorts of veggies. Iiiiit’s… sow time!

Autumn Roots, Salad Leaves and Herbs

Some root vegetables can be in and out before temperatures take a dive for winter, although they will also happily remain in the ground during winter in milder areas. This includes maincrop carrots, beetroot, summer radishes, and turnips. They’re all perfect for sowing into ground that’s been left vacant after harvesting vegetables like early potatoes. You can also sow loose-leaf or non-hearting lettuces to keep the salad bowl full right through into autumn.

Once you’ve sown your seeds, give them a thorough watering with cold water. On warm days it’s a good idea to delaying sowing until the evening, when it’s cooled down a bit, and if it’s really hot you can cover the rows with thick netting or planks of wood to help keep the soil shaded, cool, and moist until the seeds germinate.

For lettuces that can be harvested in winter choose a winter-hardy variety, and sow a few weeks after your loose-leaf varieties. To save space in the garden, sow the seeds into plug trays first then plant them once you have space in the greenhouse or in garden beds. If planting outside, when it turns cold protect them with cloches, horticultural fleece or cold frames.

Summer is a great time to be sowing hardier leafy herbs like coriander and parsley, which are less likely to bolt after midsummer.

If you live somewhere with very mild winters you may also be able to sow other last-minute crops like early or fast-maturing varieties of cucumber, beans and courgettes. Sometimes the variety description on the seed packet will tell you how many days it takes to go from seed to harvest, and you can use that and your first expected frost date to work out whether there’s still time to grow it. (You can find your frost dates in the Location & Frost Dates area of your Account Settings in our Garden Planner.) As an example, if there are 90 days until your first frost date and your seed packet says the plant will take just 75 days to reach maturity, then go ahead and sow it – but only do this if your garden tends to enjoy consistent warmth throughout late summer and autumn.

Winter-Hardy Vegetables to Sow Now

Some hardy vegetables like spinach, Swiss chard, and spring cabbages will sit out the cold months to give a harvest during the winter or next spring.

Spinach and chard make excellent greens for winter and early spring harvests. Young leaves can be added to salads, while older ones can be steamed or stir-fried. Like many cool-season vegetables, spinach and chard are far less likely to bolt if sown in late summer.

Spring cabbages are excellent for plugging the hungry gap – that lean period when winter crops are finished, but next year’s first harvests are still out of reach. Sown now, they’ll be ready to plant next month and harvests will follow from mid to late spring.

If you garden in a very hot climate, you may need to germinate all of these cool-season greens inside your house, in the cool of the air conditioning, before gradually acclimatising them to outdoor conditions somewhere out of harsh sunlight. When you plant them in their final positions make sure to keep the soil nice and moist, and offer additional shade if necessary until temperatures cool in autumn.

Autumn-planting onions (also known as Japanese onions) can be started from seed now. Sow them into a seedbed to grow on into young plants, which are then dug up and transplanted into their final positions. Or you could start them a little later from sets, which are tiny immature bulbs.

You can also sow winter-hardy spring onions now too, which will overwinter to give mild-tasting salad onions next spring.

Potatoes for Christmas

You can find summer planting seed potatoes in some garden centres, and if you grow them in large containers they will give you a crop of potatoes later on in the autumn or early winter - maybe even for Christmas dinner! Choose a container at least 14 inches (35cm) in diameter. Lay four inches (10cm) of potting mix in the bottom of your container and plant three seed potatoes, each with the end with most shoots pointing upwards. Cover them over with a little more potting mix.

Keep them well-watered, and when the leaves push through keep adding more potting mix until you've reached the top of the container. Once temperatures begin to cool off, move the pot somewhere sheltered, such as inside a greenhouse.

Transplanting in August

In my part of the world it’s a little late now to sow some of the winter brassicas like kale and sprouting broccoli. However, you’ll still find young plants for sale that are ready to plant, so you may want to seek those out. If you can’t find plants for sale, then try sowing kale for tender salad leaves, for instance the beautifully pink and crinkled ‘Red Russian’ variety.

With any of our late-season and into-winter crops, you can easily extend the growing season by covering them up with a double thickness of horticultural fleece, a cold frame, cloche, or mini tunnel, or by growing them inside a polytunnel or greenhouse. That little bit of extra protection can extend the growing period by as much as four weeks, while kicking off spring up to a few weeks earlier too. Not bad!

Phew! There’s loads to be sowing and planting right now, and we haven’t even touched on all the delicious Asian greens, or the green manures you can sow now to keep your soil in fine fettle. Raid that seed box and get sowing!

Plants Related to this Article

Beetroot Grow Guide

Carrot Grow Guide

Radish Grow Guide