Jobs to Do in the Garden This Autumn

Autumn: The Season That Sets Up Next Year

There is a particular quality to the light in late September, when the shadows lengthen and the first dew sits heavy on the lawn until mid-morning. For gardeners, this is not a winding down but a change of gear. The soil is still warm from summer, the air is cooler, and rainfall is more reliable. Roots establish quickly in these conditions, weeds grow more slowly, and anything you plant now has a head start that spring sowings simply cannot match. Autumn is, quietly, the most productive season of the year for getting ahead.

What follows is a practical list of jobs for the coming weeks, arranged roughly in order of urgency. Work through them as time and weather allow, and don't worry if you don't manage everything. A garden is forgiving.

Tidy Borders Without Stripping Them Bare

Resist the urge to cut everything to the ground in one energetic afternoon. Many perennials, grasses and seedheads offer structure through winter, hold frost beautifully, and provide food and shelter for insects and birds. Leave sedums, teasels, echinacea, ornamental grasses and any hollow-stemmed plants standing until late winter or early spring.

What you should clear is anything diseased or slimy. Remove spent annuals, collapse-prone stems and any foliage showing signs of mildew, rust or black spot, and bin it rather than adding it to the compost heap. Cut back faded herbaceous plants that have flopped and gone brown, and lift and divide any clumps that have become congested. Autumn division suits most perennials, giving roots time to settle before the cold.

• Mulch bare soil with well-rotted manure or garden compost, but leave a gap around stems and crowns to avoid rotting.
• Edge lawns and re-cut bed edges now while the ground is soft — it makes the whole garden look cared for.
• Empty and clean water butts' gutters and check downpipes before the winter rains arrive in earnest.

Sow Green Manure on Empty Ground

Bare soil over winter loses nutrients to rain and grows a crop of weeds you didn't ask for. Green manures solve both problems at once. They cover the ground, suppress weeds, protect the soil structure from heavy rain, and can be dug in or left to break down in spring to feed the next crop.

Choose according to how long the ground will be empty. Field beans and grazing rye are hardy and ideal for overwintering, sown from September to November. Winter tares fix nitrogen and suit heavier soils. Mustard and phacelia are faster but tender, so sow them early if you want them to do anything before the frosts. For a quick fix on a small plot, agricultural mustard sown in early September will germinate within a fortnight.

• Clear weeds first — green manure will not out-compete established perennial weeds.
• Rake the surface to a fine tilth, scatter seed thinly, and rake again to cover.
• Water if the weather stays dry for more than a week after sowing.
• Cut down before the plants set seed, and either dig in or leave on the surface as a mulch.

Lift Tender Bulbs and Tubers Before the Cold Bites

Dahlias, gladioli, cannas, begonias and crocosmia will not survive a proper frost in the ground. Wait until the first light frost blackens the foliage — that signals the tubers have finished growing — then lift them carefully with a fork, working well clear of the crown to avoid spearing the tubers.

Shake off excess soil, cut stems back to a few centimetres, and let the tubers dry somewhere airy and frost-free for a week or two. Label them as you go; every dahlia looks identical in February. Store in trays of dry compost, vermiculite or newspaper in a cool, dark, frost-free place, and check them monthly for rot or shrivelling.

If you garden in a very mild coastal spot, you may get away with leaving dahlias in the ground under a thick mulch of bark or straw. Elsewhere, lifting is the safer bet.

Plant for Spring and Look After the Soil

Autumn is the best time to plant almost anything woody. Bare-root roses, fruit trees, hedging and shrubs establish far better planted now than in spring, while the soil is warm and moisture is plentiful. Order bare-root stock for delivery from November onwards, and prepare planting holes in advance, mixing in plenty of organic matter.

Spring bulbs are the other essential autumn planting. Get daffodils, tulips, crocus, alliums and snowdrops into the ground by the end of November, planting tulips a little later than the rest to reduce the risk of disease. Plant at roughly three times the bulb's own depth, in generous drifts rather than single lines.

• Spread compost over beds and let worms work it in over winter.
• Plant garlic and overwintering onion sets.
• Sow sweet peas in deep pots for strong plants next summer.
• Move containers onto pot feet to prevent waterlogging.

Protect, Feed and Feed the Wildlife

Clean and sharpen your tools before putting them away, and drain hosepipes and irrigation lines to prevent splitting. Insulate outdoor taps and bring terracotta pots indoors or raise them off the ground so they don't crack.

Keep feeding the birds as the natural supply of berries and insects dwindles — high-fat foods and sunflower hearts are ideal. Leave a pile of leaves in a quiet corner for hedgehogs, and resist tidying every last seedhead. A little mess is habitat.

Finally, take a moment to note what worked and what didn't this year. A few lines in a notebook now, while the beds are still fresh in your mind, will save you a great deal of guesswork next spring.