Jobs to do in September

Harvesting top fruit such as apples and pears begins in earnest in September. Plums and autumn-fruiting raspberries are also picked now. 

Sowing and planting

Fruit

• Continue planting new strawberry beds.

Vegetables

• Continue to sow vegetables for overwintering, including:  spinach, winter lettuce, rocket and salad leaves.
• Plant overwintering onion sets. Birds will often peck newly planted sets out of the ground, so protect them with biodegradable fleece or reused netting until they’ve rooted in.
• Spring cabbages that were sown in July or August are probably ready for planting out. Cover them with reused netting to stop pigeons shredding them.
• Cover bare areas by sowing green manures such as winter tares 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

Pruning and training

Fruit

• Finish tying in shoots on fan-trained and other wall-trained trees.
• Cut back old canes of blackberries and hybrid berries after fruiting and tie in the new canes. Left unpruned, plants will grow into a tangled, thorny mass of stems that generally fruit less and are difficult to harvest. Chop old stems into short lengths before adding them to your compost heap.

Prevention

• Check 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 during dry spells. Aim to keep the compost or soil consistently moist, ideally using stored rainwater.  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.

General 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.
• Check if plants in containers need watering. Use your finger to feel the moisture level at 2–3cm (1in) below the surface and water if the compost is dry. If possible, use stored rainwater.

Vegetables

• When asparagus foliage turns brown, it is time to cut it down. Take care as the old stems can scratch your hands and arms. Give the plants a good mulch afterwards with well-rotted organic matter, such as homemade compost.
• 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.