A wet British winter is hard on grass. Weeks of rain, combined with low light levels and cold soil, leave the sward weak and thin. Where water pooled, roots suffocate and the grass dies back, leaving pale, squelchy patches that turn to bare mud. Where you walked to the shed or hung out the washing, the soil compacts and the grass thins. And wherever drainage is poor, moss moves in to fill the gap.
Before you do anything, walk the lawn — gently — and make a note of what you find. Firm, bare patches, spongy areas that squelch underfoot, and thin, yellowed turf each need slightly different treatment. It helps to know which is which so you don't waste seed, or your own time.
This is the hardest part. The temptation in early March is to get out there and start fixing things, but grass seed and grass roots both need warmth to work. Soil temperatures of around 8–10°C are the rough threshold, which usually means late March in southern England, mid-April in the Midlands, and late April or early May further north and in Scotland.
A simple test: push a fork into the soil. If it goes in easily, and the soil is crumbly rather than claggy, you're close. If it's still cold, wet and sticky, wait another week or two. Working wet soil is the quickest way to make compaction worse.
Whatever you do, don't work a lawn that's still waterlogged. Keep off it as much as possible in the meantime, and if you have to cross it, lay down a few planks to spread your weight.
Aeration is your first job on the squelchy areas, and it's the single most useful thing you can do for a struggling lawn.
Do this when the surface is dry enough to walk on without leaving deep footprints. If the lawn is too wet for that, it's too wet for aeration.
Once the ground has warmed and the worst water has drained away, bare patches will benefit enormously from overseeding. Choose a seed mix that matches the rest of your lawn: fine fescue and bent for a smart ornamental lawn, or a harder-wearing ryegrass blend for a family lawn that takes a battering.
If rain isn't forecast, water gently with a fine rose and keep the surface moist for the first two or three weeks. New grass is surprisingly thirsty for something so small.
The most important rule is the simplest one: stay off the grass until the new shoots are established. A newly seeded patch is fragile, and a few careless footsteps can undo weeks of waiting. Give it a good four to six weeks, and longer if the weather turns cold again.
When the new grass reaches about 5–6cm, give it a first trim with sharp blades on the highest setting. Never take off more than a third of the leaf in one cut, and avoid cutting a new lawn too short in its first season.
Hold off on any weed and feed products until the new grass has been cut at least three or four times, and keep moss killers away from freshly sown areas — most will damage young seedlings. If moss is a long-standing problem, deal with it after the new grass is established, then look at drainage and shade as the underlying causes.
Once you've repaired the worst of the damage, a little forward planning makes a real difference. Aerate twice a year, in spring and autumn, to keep the soil open. Top dress lightly each autumn. Improve drainage at the edges of the lawn if water is sitting there repeatedly — a shallow channel filled with gravel can work wonders. And keep the mower blades sharp: clean cuts heal faster, and a stressed lawn is a lawn that suffers more in a wet winter.
British winters will always be unpredictable. But a lawn with decent structure, a bit of air in the soil and a thick sward will come through the next one far better than one that's been left to fend for itself.
The Seasonal Plot shares practical, down-to-earth guidance on british seasonal gardening and outdoor living for readers across the UK.
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