A wet British winter seldom arrives politely. One week you are deadheading in a thin jumper, the next the Atlantic has parked itself overhead and the lawn has become a shallow pond. Waterlogged soil and repeated frost do more lasting damage to gardens than any single cold snap, and most of that damage is preventable. An afternoon or two of preparation now will save you a great deal of replanting in spring.

Sort the drainage before the rain settles in

Water is the real enemy. Cold alone rarely kills a hardy plant, but roots sitting in sodden soil through December and January will rot quietly away. Walk your garden after a heavy shower and note where puddles linger for more than a day. Those are your problem spots.

On heavy clay, fork over the surface of beds to open up the top few centimetres, then work in well-rotted organic matter. Do not dig clay when it is wet — you will smear it into an airtight pan that holds water even longer. If a bed floods every year, consider raising it with a timber-edged bed or a mound of soil and compost, which lifts roots clear of the water table.

• Fork compacted paths and borders so rain can penetrate rather than run off.
• Add grit or coarse sand to the base of planting holes for anything that hates wet feet, such as lavender, rosemary or alpines.
• Check that any soakaway or drainage channel is clear of silt and leaves before the worst of the weather.

Empty, raise and shelter your pots

Containers take the hardest hit. Compost in a pot stays wetter than open ground, and a terracotta pot that freezes while saturated will crack or flake. A plastic pot survives the frost but can still drown its occupant.

Start by removing saucers, which trap water against the base. Stand every pot on feet, bricks or timber offcuts so surplus water drains freely instead of pooling underneath. If you have a paved patio that floods, move pots onto gravel or a shelf. Grouping containers together against a house wall gives them shared warmth and shelter from driving rain.

Wrap terracotta and glazed pots in bubble wrap or hessian, tied around the pot rather than the plant, and raise tender specimens into a cold frame, porch or unheated greenhouse. Water far less from now on — damp compost plus cold is a recipe for rot. Stop feeding entirely until spring growth restarts.

Clear the gutters, gullies and water butts

Most winter flooding around a home begins with a blocked gutter. Once leaves dam the flow, water cascades down the wall, saturates the border beneath and finds its way into sheds and conservatories. Clear gutters, downpipes and gullies now, and again after the last leaves fall.

• Fit a leaf guard or mesh over gutter outlets and the top of water butts.
• Check that water butt overflows run away from the house, not into the border.
• Clear grids and channel drains of moss and silt before the first storm.
• Sweep fallen leaves off paths and lawns rather than letting them smother the grass.

Those swept leaves are not waste. Bag them in a bin liner with a few holes punched in the side and leave them behind a shed; by next autumn you will have beautiful leaf mould to spread on beds.

Mulch beds, but keep it off the stems

A generous mulch of well-rotted manure, compost or leaf mould insulates roots against frost, slows water loss and suppresses winter weeds. Spread it five to eight centimetres deep over damp, unfrozen soil — mulching onto frozen ground simply traps cold in.

Keep the material clear of trunks, crowns and stems. Piling mulch against a crown holds moisture where it does the most harm and encourages rot in plants as varied as roses, clematis and lavender. For alpines and silver-leaved plants, use a layer of horticultural grit instead, which keeps foliage dry and rot at bay.

Protect tender plants and leave a little wildness

Move citrus, olives and tree ferns under cover if you can. For those staying outside, wrap the trunk of tree ferns with straw or fleece, and drape horticultural fleece over tender crowns on frosty nights, removing it on mild days so plants do not stew. Lift dahlia tubers after the first blackening frost and store them somewhere cool and dry.

Resist the urge to tidy everything. Seed heads on sedum, teasel and coneflower feed birds through the lean months, and hollow stems shelter overwintering insects. Leave a corner of long grass, a pile of leaves and a few undisturbed log stacks. Frogs, hedgehogs and ground beetles will repay you by eating slugs and aphids come spring.

Finally, do not walk on wet lawns or borders more than you must, and keep a pair of wellies by the back door. A garden prepared properly in autumn asks very little of you until the sap starts rising again.