What to Do in the Garden in September (UK)

Sow and plant

• Start planting spring bulbs: crocuses, daffodils, hyacinths, bluebells and snake's-head fritillaries in pots and borders (hold tulips back until later in autumn).
• Divide herbaceous perennials that have formed congested clumps.
• Collect and sow seed from perennials and hardy annuals.

Prune and tidy

• Clean out cold frames and the greenhouse ready for autumn use.
• Keep deadheading late-summer flowers to extend the display.

Lawn and general care

• Sow or repair lawns while the soil is still warm and autumn moisture is on the way.
• Net ponds before autumn leaf fall begins in earnest.

Harvest

• Pick apples and pears as they come ready, testing by lifting and gently twisting the fruit.
• Keep picking autumn raspberries.
• Dig up remaining maincrop potatoes before slug damage builds up.

Regional adjustment

Autumn arrives earlier in the north: colder northern gardens should get bulb planting and lawn work done sooner in the month while soil warmth lasts, while milder southern and western gardens have more slack later into autumn.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• RHS — Gardening in September: jobs to do this month — September top jobs include dividing perennials, collecting seed and planting bulbs for next spring; September planting lets bulbs root before soil gets too damp, protecting against winter rot.
• RHS — Bulbs: planting tips — Spring bulbs including crocuses, daffodils, hyacinths, bluebells and snake's-head fritillaries are planted in autumn in pots and borders.

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