Gardening jobs this month: September

From Prima gardening expert Ann-Marie Powell

■ Lift, divide and replant overgrown clumps of herbaceous perennials.
■ Buy or make a compost bin to take autumn debris. Read more on building a compost bin
■ Plant new perennials.
■ Remove spent summer annuals and replace with spring bedding such as wallflowers and forget-me-nots.
■ Continue planting spring-flowering bulbs in beds, borders, pots and grass.
■ Sow hardy annuals, such as marigolds, centaurea and California poppies.
■ Begin moving tender plants into sheltered positions or into the greenhouse or conservatory. Read more on plants for the conservatory
■ Carry out autumn lawn maintenance, including aerating, scarifying, top dressing and feeding. Reseed bare patches, and create new lawn from seed. Read more on growing a lawn from seed
■ Plant garlic, winter lettuce, turnips, spring cabbages and autumn onion sets in the vegetable garden.
■ Prune climbing roses when they've finished flowering, removing dead, damaged and diseased stems.
■ Lift and divide congested clumps of herbaceous perennials.
■ Plant bulbs.
■ Cut back the canes on summer-fruiting raspberries.
■ Take box cuttings.
■ Clear tomatoes out of the greenhouse.
■ Tidy up hedges and topiary with a trim.

From Country Living gardening editor Stephanie Donaldson

Garden care

■ Feed flowers and vegetables with an organic liquid feed to extend the season.
■ Sow green manures (eg mustard) in the vegetable garden.
■ Japanese anemones can be divided after they have flowered. Take 5cm root cuttings and lay horizontally in a tray half-filled with potting compost, cover with more compost and stand them in a cold frame.
■ Lift and divide woodland and water irises into smaller clumps and replant immediately.
■ Take cuttings of roses and Mediterranean plants such as lavender, rosemary, santolina and bay.
■ Root box cuttings in sharp sand.
■ Ventilate indoor grapes as much as possible to reduce the risk of mildew.
■ When blackcurrant leaves drop, take cuttings of pencil thickness 20-25cm long. Cut just above and below a bud, top and bottom. Insert in the ground so that two buds are above the soil.
■ Peg down shoots of blackberries, loganberries and tayberries to send out roots and make new plants.
■ Strawberry patches should be moved every four or five years. This is an ideal time to do so, giving the plants a chance to establish themselves in time before fruiting next year.
■ Extend the season by giving an organic liquid feed to flowers and vegetables

Insects and pests

■ Banish vine weevils with nematodes available from www.greengardener.co.uk
■ Pick caterpillars off brassicas. Severely infested nasturtiums are best pulled up and removed.
■ Cut back asparagus foliage and rake over the bed to reduce problems from pests and diseases.

Harvesting

■ Pick sweetcorn as soon as the silk starts to shrivel and turn brown. Ideally eat within half an hour of picking.
■ Lift main-crop carrots.

Planting and sowing

■ This is the best time of year to sow grass seed. Once sown, cover the area with horticultural fleece to protect from birds and maintain warmth and moisture. Remove after a month.
■ Sow winter salads.
■ Sow cornflowers, calendula, nigella and other annuals outdoors for early flowering next year.
■ Plant prepared bulbs for indoor flowering around Christmas.
■ Plant garlic and hardy onion sets.
■ This is a good time of year to plant clematis - the root system can establish itself over winter.
■ Speed up ripening of outdoor tomatoes by laying the plants down on a bed of straw and covering them with a cloche
■ Plant out biennials such as wallflowers, foxgloves and forget-me-nots

Get ready for colder weather

■ Net your pond before the leaves start to fall.
■ Move tender conservatory plants back inside.