Getting Your Garden Ready for Winter: A Checklist

There's a comforting myth amongst new gardeners that winter is simply the season where nothing much happens — you down tools in October, retreat indoors, and emerge in March to survey the damage. In my experience, that's exactly backwards. The work you put in over these quiet weeks is the single biggest factor in what survives and what doesn't.

Here's the thing most people get wrong: plants rarely die from cold itself. They die because their owner didn't prepare in time, or made a small, easily-avoided error — mulching tight against a stem, letting pond water freeze solid, or scalping the lawn just before the first hard frost. The real villain isn't temperature. It's the freeze-thaw cycle, where water expands inside plant cells and ruptures them from the inside out.

This checklist is built around four pillars: protecting your plants, your tools, your pots and containers, and your pond. Work through it methodically and you'll spend far less time replacing dead specimens — and considerably less money — next spring.

The Science of Frost Damage (and Why It Matters)

Before we get to the tasks, it's worth understanding what you're actually protecting against, because it changes how you approach everything that follows. When the temperature drops below 0°C, the water inside plant cells freezes and expands by around nine percent. That expansion ruptures the cell walls, turning firm, healthy tissue into mush. It's the same reason a forgotten can of fizzy drink splits in the freezer.

Different plants have wildly different tolerances. Most plants will freeze when temperatures sit at around 28°F (roughly -2°C) for about five hours. Tropical specimens are far fussier — some give up at 40°F (4°C), others at 35°F (2°C). Tender seedlings, with all that soft new growth, often perish when the mercury merely touches 32–33°F (0°C). At the hardy end of the spectrum, some plants shrug off temperatures down to 18–20°F (-7 to -9°C) without complaint.

The practical takeaway is this: you don't need to protect everything equally. Knowing whether a plant is genuinely tender, borderline-hardy, or bombproof tells you exactly how much effort it deserves. Wasting fleece on a hardy shrub whilst leaving a pelargonium to freeze is a classic beginner's mistake.

Pillar One: Protecting Your Plants

This is where most of your autumn energy should go, and where timing matters most. The job splits neatly into three categories: tender things you bring indoors, borderline things you insulate in place, and tubers you lift and store.

Bringing Tender Perennials Under Cover

Pelargoniums (what most of us still call geraniums), cannas, citrus trees and young cordylines have no business sitting outside through a British winter. Move them into a greenhouse, conservatory, or a bright porch before the first frost threatens. A cold but frost-free space is ideal — they don't need warmth, just protection from freezing.

Lifting and Storing Tubers

Dahlias, gladioli and cannas are the headline acts here. Once the first frost has blackened their foliage — and that's your cue, not a date on the calendar — dig up the tubers carefully. Let them dry out on newspaper for a few days, then pack them in dry peat moss or shredded newspaper and stash them somewhere dark and humid at 40–50°F (5–10°C) until spring.

Mulching: The Most Misunderstood Job in the Garden

Mulch is your insulating blanket, trapping a layer of warmer air and stopping the soil from freezing too quickly. A thick layer of 2–3 inches around the base of plants and shrubs provides genuine insulation, helps the soil retain moisture, and slows freezing. For borderline-hardy plants you can go heavier — four to six inches around the crowns — to really buffer them against the worst of it.

In practical terms, October is your mulching month. Apply 7.5–10cm of mulch around the crowns of your borderline-hardy plants whilst the soil still holds a little residual warmth from summer. Mulching cold, sodden ground in December achieves far less.

Pillar Two: Protecting Your Tools

This is the pillar everyone skips, and it's the one that quietly costs you the most over the years. A neglected spade goes rusty, a blunt secateur tears rather than cuts (which spreads disease), and a cordless battery left in a freezing shed can be ruined by spring. Winter is the perfect downtime to give your kit some long-overdue attention.

Clean, Disinfect, Sharpen, Oil

Work through your tools in that order. Scrape off the caked soil and sap first — there's no point disinfecting a layer of mud. For disinfecting blades and pruning tools, the Royal Horticultural Society's guidance is to leave the disinfectant in contact with the surface for 15–20 minutes before wiping off, which is long enough to actually kill the pathogens that cause problems like canker and blight.

The Battery Trap

If you've gone cordless — and most of us have for trimmers, mowers and blowers — there's one rule that catches people out every single year. Never leave cordless tool batteries in a freezing shed over winter. Bring them indoors and store them at around 50–70% charge (or whatever your manufacturer recommends) to keep the cells healthy. A fully drained or fully charged battery left to freeze can lose a chunk of its lifespan permanently.

Don't Forget the Mower

Keep mowing at 30–35mm during mild, frost-free spells right up until the grass stops growing — but stop the moment the ground is frozen or waterlogged. Walking a heavy mower over sodden turf compacts and damages it, and cutting frozen grass shreds the blades' tips. Once you've finished for the year, clean the deck, and your mower will thank you in spring.

Pillar Three: Protecting Pots and Containers

Pots face a problem that plants in the ground don't: their roots are exposed on all sides, with only a thin wall of terracotta or ceramic between them and the freezing air. Worse, the pots themselves can be destroyed. Terracotta and unglazed ceramics are porous — they soak up water, and when that water freezes and expands, it cracks and flakes the pot apart from the inside.

Save the Pot, Save the Plant

There are three jobs here, and October is the time to do them. First, move any non-frost-proof ceramics under cover — into a shed, greenhouse or against a sheltered house wall. Second, wrap the pots you can't move in bubble wrap or hessian to insulate the rootball. Third, raise everything onto pot feet so excess water drains freely rather than pooling and freezing around the roots.

Pillar Four: Protecting Your Pond

Ponds are the trickiest of the four pillars because there's living wildlife to consider — fish, frogs, beneficial bacteria — all of which respond to the cold in their own way. Get the timing right and your pond sails through winter untouched. Get it wrong and you risk losing fish to a sealed-over, oxygen-starved surface.

Pumps, Fountains and the First Frost

Remove pond pumps and fountains before temperatures reach freezing — in most of the UK that means late October or November. Leaving a pump running through a hard freeze can damage it, and a fountain that keeps churning the water actually chills it faster, which is the opposite of what your fish need. Clean the pump, store it somewhere frost-free, and your pond will hold a more stable temperature.

Looking After the Fish

Fish slow right down as the water cools, and their digestion grinds to a halt. Stop feeding them once the water drops below 10°C — any food they can't digest simply rots in their gut or fouls the water. Before winter properly sets in, do a partial water change of 25–30%. This reduces the nitrate levels that build up over time and can cause real problems for fish in a sealed-over pond.

Managing Ice

The danger of a completely frozen surface isn't the cold underneath — it's that the ice seals in toxic gases from decomposing matter and seals out oxygen. The fix is simple and gentle: float a ball on the surface so it keeps a small patch from freezing, or use a pond de-icer. Whatever you do, never smash the ice with a hammer — the shockwave can stun or kill fish. If you need to open a hole, melt it gently by resting a pan of hot water on the surface.

Pond Plants

Hardy water lilies will happily overwinter outdoors provided their crowns sit below the ice line — usually 18–24 inches deep. If yours are in shallow water, lower the baskets to the deepest part of the pond. Tender, tropical marginals are a different story: lift them and store them indoors at 45–60°F (7–15°C) until the danger of frost has passed.

Your Month-by-Month Timeline

Knowing what to do is only half the battle; knowing when ties it all together. From October through to February there are fewer visible jobs than in the growing season, but the work done in these months is precisely what pays off when spring arrives.

October is unquestionably the keystone month. Apply your 7.5–10cm of mulch around borderline-hardy crowns, lift the dahlia tubers once frost has blackened them, remove the pond pump and fountain before freezing, begin pruning your apple and pear trees, move non-frost-proof ceramics under cover, and wrap your remaining pots in bubble wrap or hessian. Front-load the effort here and the rest of winter is gentle maintenance.

The Essential Winter Kit

You don't need to spend a fortune to do this properly. A handful of inexpensive consumables covers almost every task across all four pillars. Here's what's worth keeping in the shed.

Common Mistakes That Cost Plants Their Lives

Over the years I've made — and watched others make — the same handful of errors again and again. They're all avoidable once you know to look for them.

Frequently Asked Questions

How Each Pillar Scores for Effort vs Reward

If your time is limited, it helps to know which jobs deliver the biggest payoff. Here's my honest assessment of where the effort is best spent.

Plants edge it for sheer return on investment — a few minutes of mulching saves an entire border. But every pillar earns its place, and tools, though least urgent, quietly save you the most money over a decade of gardening.

Who Needs to Worry Most?