Vegetables to plant in September: 8 delicious crops to get growing this month

There are many vegetables to plant in September, which may come as a surprise. The peak growing season is indeed starting to wind down, but some quick-growing crops will give you harvests as the temperatures drop, while others can be planted for overwintering, getting you ahead for spring.

For instance, if you like the idea of picking homegrown garlic or onions next year, now's a good time to plant them. Many leafy greens can be sown now, too, from colourful chard to spicy mizuna. Whether you're an experienced grower or a beginner at vegetable gardening, there are lots of opportunities to keep your green fingers busy.

Below, you'll find eight top picks for planting, alongside tips on how to go about it. You'll also find plenty of recommendations on specific varieties to grow.

8 vegetables to plant in September for a delicious homegrown harvest

As we head into the cooler months, bear in mind that newly planted crops outdoors may need protecting from frost, which can be achieved using horticultural fleece. A good gardening trowel for digging, a pair of sturdy gardening gloves, and plant labels so you remember what's planted where (we like these wooden ones from Crocus), will also make your growing endeavours easier.

1. Hardy Spinach

"Leaves for salad or cooking are great to get a last sowing in now," says Nelly Hall, brand director at Alitex. "Spinach is always a great staple as it is good for picking as small leaves for salads, and if there are any you let mature, they are great for cooking too."

"'Giant Winter' is a great variety for this time of year," Nelly adds. Another hardy option, recommended by the GardeningExpress team, is "Medania".

Spinach is fast-growing and can be grown in large containers if you don't have raised beds. The seeds can be sown directly into nutrient-rich soil. Thin the seedlings out as they grow if needed, and keep the crop well-watered. As temperatures cool, you may need to protect the plants from frost using horticultural fleece. You could also consider growing the plants in a greenhouse if you have the space.

Nelly Hall

Nelly Hall is the brand director at Alitex, the renowned British aluminium greenhouse specialist. With a deep passion for design and horticulture, she champions the craftsmanship and structural intricacies of greenhouses. Since launching the first National Trust Collection of greenhouses in 2004, Nelly has played a key role in expanding the collection to eight designs, establishing a growing overseas market, and securing a prestigious endorsement from the Royal Botanic Gardens, Kew.

2. Chard

"Another I love to sow is chard," says Nelly. "It looks great in the garden and is a very tasty green leaf to eat. Sow early September ideally, then pot on as they develop into open beds in your greenhouse if you have them.

"Try 'Ruby Chard' or 'Bright Lights' – the stunning classics!" Nelly adds. You can shop for "Bright Lights" seeds from Thompson & Morgan.

Chard grows well in well-draining, rich soil, so add plenty of homemade compost to your planting site. Crops sown this month can be overwintered with a bit of protection from the elements, giving you an early harvest come spring. Be sure to watch out for slugs.

3. Cut-and-come-again Salad Greens

Huw Richards, a grow-your-own expert working with Gardena, recommends growing mustards and mizuna now, as well as rocket. "These Asian and Mediterranean salad crops are incredibly fast to mature, ready to start harvesting in just three to four weeks," he says. "They are also cut-and-come-again, so rather than pulling up the entire plant, you simply harvest the outer leaves and leave the centre to regrow."

Nelly also suggests sowing mustards and mizuna now. "Sow in modules for ease of transplanting out, and when they are about an inch tall, transplant them into open beds or into large pots or troughs." Water them (but not too much), to keep them growing, she adds.

Try "Red Empire" mizuna from Suttons for deep purple leaves.

4. Garlic

Andrew White of Rhino Greenhouses says that garlic can be planted in your greenhouse between September to November. He recommends preparing a large pot or container with sufficient draining holes, with well-draining soil.

"When planting your garlic cloves, ensure that the rounded end of your clove is positioned at the bottom and the point of your clove is facing upwards." He also advises keeping the soil moist, but not waterlogged. You can plant them out in the spring.

Don't expect a crop any time soon – Andrew notes that it won't be ready for harvesting until well into next year. The trick is to look at the foliage – "if the leaves become soft and appear to wither, it's time to harvest."

Suttons has a range of autumn-planting garlic available.

Andrew White

Andrew has nine years of experience in gardening-related topics and specialises in greenhouse growing and seed sowing. Andrew is head of sales and marketing manager at Rhino Greenhouses, so when he's not in his garden sowing the seeds for all manner of fruits, vegetables and plants, he is helping garden enthusiasts find the right products that fit their garden space.

5. Turnips

Andrew says turnips are a great plant to grow in September as they will be ready for harvest within as little as six weeks after planting.

The GardeningExpress team also recommends sowing them now and highlights their versatility, "as both the sweet roots and the peppery green tops are edible, providing two crops in one. They work beautifully in everything from roasted vegetable trays to warming winter stews."

"Planting your turnips in your greenhouse, instead of directly in the ground, offers your turnips an added layer of protection from the unpredictable weather we often have in September," Andrew continues. Ensure you’re planting in a large container with good-quality multi-purpose soil, he adds. "Water your turnips regularly, and harvest when they are roughly the size of a golf ball."

Try "Sweetbell" from Crocus for a crisp and sweet crop.

6. Spring Onions

"Spring onions are extremely low-maintenance plants to grow and make great additions to our greenhouses in September," says Andrew. If you plan to transplant them in the future, he recommends planting them in seed trays – otherwise, sow them directly into a pot or container. Either way, ensure they have good drainage.

Alternatively, you can plant spring onions directly outdoors for harvesting in spring – try winter-hardy varieties such as "White Lisbon", available at Suttons.

7. Radishes

Huw also recommends growing winter radishes at this time of year. Like turnips, he says they're great if you're looking for crops to slot into the empty space in your garden, ensuring no patch of soil goes to waste.

"They cope well in cooler conditions, and by sowing now, you can keep pulling fresh roots through autumn." Winter radishes are often cooked before being eaten. Varieties include "April Cross" and "Black Spanish Round", which you can buy from Suttons.

A last crop of salad radishes can also be sown directly now before it's too late – try "French Breakfast 3", also available from Suttons. Thin seedlings as they appear. A good gardening tip to remember is to harvest them before they turn woody (they will be ready in just a few weeks).

8. Onions

Onions are a staple ingredient in most kitchens, and growing your own is super satisfying and enables you to try a range of varieties. By planting the sets now (which are the immature bulbs), you can get a head start on your crop.

Pick somewhere sunny that drains well, and plant each bulb just below the soil surface, so that the tips are just visible. Keep the site free from weeds as they grow. Like garlic, they'll be ready to harvest in summer next year.

Thompson & Morgan has a mixed pack for autumn planting, which includes white, brown, and red varieties.

FAQs

What vegetables should you avoid planting in September?

"Don’t be tempted to sow summer favourites like courgettes, beans, or sweetcorn this late in the year," says Huw. "They won’t have the warmth or daylight hours needed to mature, and you’ll end up wasting precious seed and bed space that could be used for crops that thrive in cooler conditions.

"It’s easy to get carried away after a heatwave and think you can squeeze in another round of summer crops, but the shorter days and cooler nights mean energy is better spent on leafy greens, hardy roots, and overwintering veggies that will give you a harvest."

How should you space your vegetables when planting in September?

Huw recommends spacing out your plantings and sowings slightly further apart than usual. This will mean that each plant can maximise light exposure for photosynthesis to help them grow as the days shorten, he explains.

As well as planting some veggies now, there are plenty of other essential gardening jobs for September to tick off. Our guide has plenty of expert advice.