What to Plant in September

September marks the beginning of autumn, but don't be fooled into thinking the growing season is over. In fact, it's one of the busiest months in the gardening calendar. The soil is still warm from the summer, rainfall usually becomes more reliable, and cooler temperatures create ideal conditions for many plants to establish strong roots.

Whether you're growing vegetables, flowers, shrubs or trees, September offers plenty of opportunities to keep your garden productive and prepare for the seasons ahead.
 

Is September a Good Time to Plant?

Yes, September is one of the best months for planting in the UK. Warm soil encourages rapid root growth, while cooler air temperatures reduce stress on newly planted flowers, shrubs and trees. It's also an excellent time to sow hardy vegetables and plant spring-flowering bulbs, ensuring your garden continues to thrive well into next year.

Vegetables to Plant in September

Although many summer crops are coming to an end, there's still plenty you can sow for autumn, winter and early spring harvests.

Garlic: Late September is the perfect time to plant garlic. Autumn planting allows bulbs to develop strong roots before winter, often resulting in larger harvests the following summer. Choose a sunny, well-drained position and plant cloves with the pointed end facing upwards.
 

Onions: Autumn onion sets can be planted from September onwards in many parts of the UK. They establish over winter and are usually ready to harvest earlier than spring-planted onions.
 

Broad Beans: Hardy varieties of broad beans can be sown in September in milder regions or started in pots for planting out later. Autumn sowings often produce earlier crops the following year.
 

Spinach:  Spinach grows well during the cooler temperatures of autumn and provides delicious leaves well into the season.
 

Winter Lettuce: Hardy lettuce varieties can be sown now for harvesting during autumn and, with protection, throughout winter.
 

Spring Cabbage:  If you haven't already sown spring cabbage, early September is often your final opportunity to establish young plants before winter.
 

Radishes: Fast-growing radishes remain an excellent choice for September sowing and can often be harvested within a month.

 

Herbs to Plant in September

Several herbs continue growing well in early autumn. Consider planting:

• Parsley
• Chives
• Coriander
• Mint (best grown in containers)
• Thyme
• Sage

Perennial herbs planted in September often establish well before winter and return strongly the following spring.

Flowers to Plant in September

Autumn is one of the best times to create colourful displays for both this year and next.

Pansies and Violas: These hardy favourites provide colour throughout autumn, winter and early spring, making them perfect for beds, borders and containers.

Wallflowers: Plant young wallflowers now to enjoy fragrant blooms next spring.

Forget-Me-Nots: September is an ideal month to sow forget-me-nots, producing cheerful blue flowers the following spring.

Sweet Williams: These traditional cottage garden favourites establish well in autumn and reward gardeners with colourful blooms next year.

 

Plant Spring-Flowering Bulbs

September is one of the busiest months for bulb planting. Popular choices include:

• Daffodils
• Crocuses
• Alliums
• Snowdrops
• Hyacinths
• Grape hyacinths (Muscari)

Most bulbs prefer well-drained soil and a sunny or partially shaded position. Tulips are generally best planted later in October or November, as this helps reduce the risk of fungal diseases.

 

Trees and Shrubs

September is an excellent time to plant many ornamental shrubs and evergreen hedges. The warm soil allows roots to establish before winter arrives, helping plants settle into their new home. Good choices include:

• Hebe
• Skimmia
• Holly
• Laurel
• Box
• Euonymus

Towards the end of the month, bare-root planting season begins for some species.


 

Fruit Garden Jobs

September is harvest time for many fruit crops. Continue picking:

• Apples
• Pears
• Blackberries
• Autumn raspberries
• Plums (where still available)

It's also a good time to:

• Plant new strawberry runners.
• Prune trained fruit trees if needed.
• Remove fallen fruit to discourage pests and disease.
• Prepare new fruit beds for autumn planting.

 

Lawn Care in September

September is often considered the best month for lawn renovation. The combination of warm soil and increased rainfall creates ideal growing conditions. Jobs to tackle include:

• Scarifying to remove moss and thatch.
• Aerating compacted lawns.
• Overseeding bare patches.
• Applying an autumn lawn feed.
• Continuing to mow, while gradually raising the cutting height as growth slows.

 

Watering in September

Many parts of the UK experience more rainfall during September, but don't stop watering completely. Pay particular attention to:

• Newly planted trees and shrubs.
• Autumn bedding plants.
• Containers.
• Vegetable crops that are still producing.

Always check the soil before watering, as cooler temperatures mean moisture lasts longer.

 

September Garden Maintenance Checklist

As the seasons change, it's a good time to prepare your garden for autumn. Tasks include:

• Deadhead late-flowering plants.
• Divide overcrowded perennials.
• Remove diseased foliage.
• Harvest remaining vegetables regularly.
• Collect seeds for next year.
• Clean out greenhouses.
• Start making leaf mould by collecting fallen leaves.
• Add spent plants to the compost heap.

 

Preparing for Winter

September is an ideal month to think ahead. Consider:

• Installing water butts to collect autumn rain.
• Cleaning and storing garden tools.
• Checking plant supports before autumn winds arrive.
• Ordering bare-root trees and hedging for later planting.
• Planning next year's vegetable rotation.

A little preparation now can make winter gardening much easier and give your plants the best possible start.

 

Frequently Asked Questions

Is September too late to plant vegetables?

No. Many vegetables, including garlic, onions, spinach, lettuce and broad beans, are well suited to September planting in the UK.

Can I still plant flowers in September?

Yes. Autumn bedding plants, wallflowers, pansies, violas and spring-flowering bulbs are all excellent choices for September.

What should I avoid planting in September?

Tender annuals and frost-sensitive plants are generally best avoided outdoors as temperatures begin to fall. Focus instead on hardy plants that can cope with cooler weather.

 

Time to get gardening this September

September is one of the most rewarding months in the gardening calendar. With warm soil, cooler temperatures and increasing rainfall, it's the perfect time to establish vegetables, flowers, trees and shrubs that will reward you over the coming months and into next spring. By making the most of September, you'll extend your growing season, prepare your garden for winter and lay the foundations for a healthy, colourful and productive garden next year. Here at Thompson's Garden Centres we have all the plants, fruit & Veg and gardening products that you need to get gardening in September.

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