There is a particular morning in autumn when the air changes. The grass is stiff underfoot, the shed roof wears a thin silver sheen, and the dahlias that were blazing away only yesterday have gone the colour of wet tissue. That first frost is a useful signal. It tells you the growing season is closing and there is a short, generous window of mild days left to get your garden ready for the cold. Spend a few weekends on the jobs below and you will lose far less to winter, and start spring with healthier soil and stronger plants.

Know Your Frost Dates and Your Frost Pockets

Frost does not arrive everywhere at once. In mild coastal Cornwall or west Wales you might not see a proper frost until December, while gardens in Aberdeenshire, the Pennines or a sheltered Shropshire hollow can be frosted by late September. The Met Office reckons the average first air frost across much of England falls between mid-October and mid-November, but your own garden has its own microclimate. Cold air drains downhill like water and pools behind walls, hedges and fences, so a low corner at the bottom of the plot will always go first.

Walk round on a still evening and note where the air feels coldest. Those are the spots to protect first, and the spots to avoid planting anything tender next year. A maximum-minimum thermometer left out overnight is a cheap way to learn exactly what your garden does.

Protect Tender Plants Before the First Cold Night

The trick with tender plants is to act while the weather is still mild, not once the forecast has turned. Aim to have everything tucked up by mid-October in most of the UK.

• Move pots to shelter. Pelargoniums, citrus, olives, agapanthus and tender fuchsias overwinter best against a south-facing house wall or in a cool, bright porch or greenhouse. Roots in a pot freeze far faster than roots in the ground, so cluster containers together and wrap the outside of the pots in bubble wrap or hessian.
• Use horticultural fleece, not plastic. Double-layer fleece over tree ferns, bananas and young tender shrubs, held off the foliage with a few canes so the leaves are not crushed. Plastic sheeting traps condensation and can do more harm than good.
• Lift and store what you can. Dahlias, cannas and gladioli are happier dried off and stored in a frost-free shed in trays of barely damp compost than left to gamble in the border.
• Water the night before a frost. Moist soil holds warmth and releases it slowly, giving a degree or two of protection. Dry soil and dry plants freeze hardest.
• Stop feeding. Nitrogen encourages soft, sappy growth that frost shreds. Switch to a high-potassium feed in early autumn, or nothing at all, to help stems firm up.

Clear Fallen Leaves — and Turn Them Into Something Useful

Leaves left thickly on a lawn will smother the grass, encourage moss and leave yellow patches that linger until April. Rake them off regularly rather than waiting for the last one to fall. On borders, a thin scattering is fine, but a heavy matted layer over small alpines or low herbaceous plants can rot the crowns beneath.

Do not put them out for the council. Autumn leaves are one of the best free resources a garden produces. Fill old compost bags, punch a few holes in the sides, damp the contents and tie the tops. Tucked behind the shed for a year, they turn into crumbly leaf mould — perfect as a seed-sowing mix, a mulch for woodland plants, or a top dressing for borders. Oak, beech and hornbeam break down slowly and make the finest leaf mould; sycamore and horse chestnut are quicker but still worth keeping.

If you have a pond, netting it now saves you a job later. Falling leaves decay in the water and feed the algae that turns it green in spring. Leave the netting in place until the last leaves have dropped, then clear it.

Mulch Borders to Insulate Roots and Feed the Soil

A thick mulch is the single most useful thing you can do for a border before winter. A layer of well-rotted manure, garden compost or leaf mould, spread 5–7cm deep, insulates roots against repeated freezing and thawing, suppresses winter weeds and slowly feeds the soil as worms pull it down.

• Spread it over damp soil, ideally after rain, but never on frozen or waterlogged ground.
• Keep it clear of stems, trunks and crowns — a collar of mulch against bark softens it and invites rot.
• Pay particular attention to newly planted shrubs, fruit bushes and anything borderline hardy such as penstemons or agapanthus.
• Light soils and raised beds benefit most, as they drain and cool quickly.

Tend Trees, Shrubs and the Wildlife That Shares Your Garden

Resist the urge to cut everything back to the ground. Seedheads of teasel, sedum, echinacea and honesty look beautiful rimed with frost and feed goldfinches through the lean months. Hollow stems and undisturbed leaf litter are winter quarters for ladybirds, lacewings and hibernating queen bumblebees, so leave a few corners wild.

Tie in climbers that might whip loose in gales, check tree ties are not cutting into swelling trunks, and give established roses a light tidy rather than a hard prune — the proper prune is a February job. Put out bird food and keep a shallow dish of water topped up; natural supplies are scarce, and a pond or birdbath is a lifeline on the hardest days. If ice forms, pour on hot water rather than smashing it, which can harm fish and pond life.

A Last Few Jobs While the Weather Holds

Clean and oil your tools before they go into the shed, empty and store hoses and watering cans, and lag the outdoor tap. Give the lawn a final cut on a high setting if it is still growing, and stay off it once frost has settled in. Insulate the greenhouse with bubble wrap, ventilate it on mild days and check that gutters are clear of leaves before the winter rain arrives. An hour spent now, on a bright October afternoon, is worth several wet ones in January.