Jobs to do in September

Harvest time

A person putting an apple into a wooden trug nestled in the grass, full of applesHarvesting top fruit such as apples and pears begins in earnest in September. The last of the plums and autumn-fruiting raspberries are also picked now. 

Sowing and planting

Fruit

Vegetables

  • Continue to sow vegetables for overwintering, to mature next spring, including: turnips, spinach, winter lettuce and oriental vegetables.
  • Plant overwintering onion sets.
  • Spring cabbages that were sown last month are probably ready for planting out. Cover them with reused netting to stop the pigeons shredding them.
  • Cover bare areas by sowing green manures such as crimson clover and Italian ryegrass to capture nutrients and protect the soil over winter. These can be dug in in spring or covered with cardboard 6-8 weeks before planting if you are practising no-dig. Video: how to choose and sow green manures

A person planting onion sets in a raised bedPruning and training

Fruit

Prevention

  • Watch tomatoes for blossom end rot, and other ripening problems. As well as affecting tomatoes, irregular watering can also cause splitting of root vegetables and flower abortion in runner beans. Help prevent this by watering well during dry spells. Video: common tomato problems and how to prevent them
  • When lifting potatoes, be sure to clear away top growth left behind to reduce the risk of blight next year, and take care not to damage the tubers so that they store better.

A person holding freshly dug potatoesGeneral care

Fruit

  • Harvest top fruit such as apples and pears. Look for fruit falling under the tree (windfalls) to indicate which apples are ready, and cup the fruit in your hand and twist upwards to check if they are ready for picking. If it comes away easily in your hand then it is ready for harvest.
  • Order cold-stored strawberry runners for delivery in spring. These fast-track your harvest, cropping around 60 days after planting.
  • Order new fruit trees, canes and bushes.
  • Continue to provide support for heavily laden fruit tree and bush branches.

A person picking apples to put into a wooden trugVegetables

  • When asparagus foliage turns brown, it is time to cut it down. Take care as the old stems can scratch your hands and arms, and give the plants a good mulch afterwards with homemade compost or manure-based soil improver.
  • If the soil is dry, water winter squash and pumpkins to prevent their growth from being checked. Use stored rainwater wherever possible.
  • Celery can be earthed up to blanch the stems for the final time this month, leaving just a tuft of foliage sticking out of the trench or collar. You don’t need to do this for self-blanching cultivars.
Learn the basics of growing fruit and vegetables: Watch Get Set, Grow! 

Gardeners' calendar

Find out what to do this month with our gardeners' calendar

Advice from the RHS

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The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.