What to Grow in September: A Guide for UK Gardeners

September marks the transition from the warmth of summer to the cool embrace of autumn. While the days are shortening, the soil still holds summer's warmth, making it an excellent time to sow, plant, and transplant a variety of crops. Whether you're looking to extend your harvest or prepare your garden for the coming spring, September offers a wealth of opportunities in the garden! Here’s a guide to what you can grow this month in the UK, along with some helpful hints and tips to make the most of your gardening efforts.

Vegetables to Sow in September

Even as the weather begins to cool, there are still several vegetables you can sow in September. These crops are ideal for providing a fresh harvest during the colder months or for getting a head start for next spring.

• Varieties: Spinach, Winter Lettuce, and Land Cress.
• Tips: Sow seeds directly into the ground or in containers. Protect the seedlings with cloches or fleece as the temperature drops. These greens thrive in cooler temperatures and can even survive light frosts, giving you fresh leaves well into winter.

• Varieties: Winter Radish (e.g., 'Mooli' or 'Black Spanish').
• Tips: Radishes grow quickly and are perfect for a September sowing. Sow them directly into the soil, spacing seeds about 2.5cm apart. Ensure the soil is kept moist to prevent the radishes from becoming too spicy or woody.

• Varieties: Early Purple Top Milan, Golden Ball.
• Tips: Sow turnips directly into the ground, spacing them about 10cm apart. These fast-growing root vegetables can be harvested in about six weeks, providing a quick autumn crop.

• Varieties: White Lisbon, Ishikura.
• Tips: Sow these directly into the ground or in containers for an early spring harvest. Spring onions are hardy and can tolerate cooler temperatures, making them a perfect crop for this time of year.

Vegetables to Plant/Transplant in September

As the growing season winds down, September is also an ideal time to transplant certain vegetables that will establish themselves over the winter and be ready for harvest early next year.

• Varieties: Solent Wight, Early Purple Wight.
• Tips: Plant garlic cloves in well-drained soil with the pointed end facing upwards, about 2.5cm deep and 10-15cm apart. Garlic needs a cold period to develop properly, so planting in September or October is ideal.

• Varieties: January King, Tundra.
• Tips: If you’ve started these from seed in previous months, now is the time to transplant them. Space plants about 45cm apart in a sunny spot with well-firmed soil. Cover with netting to protect from pigeons and other pests.

• Varieties: All Year Round, Snowball.
• Tips: Transplant seedlings into fertile soil, spacing them 60cm apart. Protect young plants from frost by covering them with fleece or cloches as necessary.

Herbs to Sow in September

Herbs are not only great for cooking but also add a lovely aroma and aesthetic appeal to your garden. While many herbs are best sown in spring, some can be started in September for an early spring harvest.

• Varieties: Curly Leaf, Flat-Leaf.
• Tips: Sow parsley seeds in pots or directly into the ground. Parsley takes a while to germinate, so be patient. It’s hardy and will survive the winter, giving you fresh leaves early next year.

• Tips: Chervil thrives in cooler weather. Sow directly into the ground in a partially shaded area. The plant can tolerate light frost and will provide fresh, delicate leaves through autumn and winter.

Flowers to Sow in September

September is also a good time to sow hardy annuals and biennials, ensuring an early display of blooms next spring and summer.

• Varieties: Old Spice Mix, Royal Family Mix.
• Tips: Sow sweet peas in pots or directly into the ground. They benefit from a period of cold to germinate and will bloom beautifully next summer.

• Varieties: Sunset Mixed, Vulcan.
• Tips: Wallflowers are perfect for providing spring colour. Sow seeds now and transplant them later in the autumn for a vivid display of blooms next year.

General Tips for September Gardening

• Soil Preparation: As you clear out summer crops, take the time to replenish the soil with compost or well-rotted manure. Break apart some Hortiwool and add this in too, to provide further nutrients and aim temperature regulation.

• Frost Protection: As the nights begin to cool, keep an eye on the weather forecast. Have your Hortiwool, or something similar to hand to protect tender plants from unexpected frosts.

• Mulching: Adding a layer of mulch around your plants can help retain moisture and keep the soil temperature stable as the weather cools.

• Pest Control: Slugs and snails can be particularly troublesome in damp autumn weather. Tear apart a Hortiwool Garden Pad and place it around the base of vulnerable plants to create a pest barrier.

September may signal the end of summer, but it's by no means the end of gardening! With a bit of planning and effort, you can continue to enjoy the fruits (and vegetables) of your labour well into winter and beyond. Happy gardening!

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