A decent lawn in the UK is mostly a matter of doing a few ordinary jobs at the right time, not buying products. Grass here grows from roughly March to October, sulks in drought, and hates being walked on when frozen. This calendar walks through the year month by month, with the mowing heights, feeds and repairs that actually make a difference.
January and February: stay off it
The most useful thing you can do for a lawn in midwinter is leave it alone. Walking on frozen or waterlogged grass bruises the leaf blades and compacts wet soil; the black footprint trails that appear after a frosty shortcut can persist for weeks. If the ground is firm and dry, February is a good moment to service the mower — sharpen or replace the blade, since a ragged cut from a blunt blade turns grass tips brown and lets disease in. Rake off twigs and leaves, and knock wormcasts about with a besom on a dry day rather than smearing them underfoot.
If grass is still growing in a mild winter — increasingly common in southern England — a light topping on a dry day does no harm, with the mower set high.
March: the first cut, set high
Once the grass is visibly growing and the soil has dried enough to walk on, make the first cut of the year — usually mid to late March, earlier in the south-west, later in Scotland and at altitude. Set the mower to its highest setting for this first pass. Scalping half-dormant grass stresses it and opens gaps for moss and weeds. Over the following weeks, lower the blades gradually as growth speeds up.
March is also the month to re-cut lawn edges with a half-moon edging iron while the soil is soft, which makes every summer trim faster.
April: feed, weed and repair
April, when soil is warm and moist and growth is accelerating, is the best month for the main spring feed. Use a spring lawn fertiliser — relatively high in nitrogen — applied evenly at the rate on the packet, ideally just before rain. Uneven application shows as stripes; overdosing scorches. If moss is a problem, this is also the conventional moment for a combined treatment, but see the moss section below before reaching for one.
April's warmth makes it a good month for repairs too: re-seed bare patches by loosening the soil surface, sowing seed, and keeping the patch moist; and re-turf broken edges by cutting out the damaged square and turning it 180 degrees so the ragged edge faces inwards.
May and June: the mowing months
Growth peaks now and mowing becomes weekly, sometimes more. The single most important habit is the one-third rule: never remove more than a third of the leaf in one cut. For a general family lawn, a cutting height of 2.5–4 cm is about right; fine ornamental lawns can go shorter, shaded lawns should stay longer. Cutting too short is the commonest lawn mistake in Britain — it weakens the grass, browns it faster in dry spells, and hands the advantage to moss and daisies.
Consider leaving the box off occasionally and letting fine clippings fly back into the sward: they return nitrogen and moisture. If you take part in No Mow May, raise the blades for the first cut afterwards and reduce height over two or three cuts rather than one.
July and August: drought — let it brown
In a dry summer the honest advice is the one people least want to hear: do not water an established lawn. Brown grass in July is dormant, not dead. The growing points sit at soil level, protected, and the lawn will green up within days of proper rain — usually by mid-September at the latest. Watering enough to keep a whole lawn green takes hundreds of litres per session, encourages shallow rooting, and is exactly what hosepipe bans exist to stop. Newly laid turf or spring-sown patches are the exception; they have no deep roots yet and do need water in their first season.
Through hot spells: raise the mowing height a notch or two, mow less often, keep the blade sharp, and leave clippings on the surface as a light mulch. Avoid feeding — fertiliser on drought-stressed grass scorches it.
September: the big renovation month
September, with warm soil and returning rain, is the most valuable month in the lawn year. Three jobs, in order:
- Scarify. Rake out thatch — the springy layer of dead material at the base of the sward — with a spring-tine rake or powered scarifier. The lawn looks dreadful afterwards; it recovers within weeks and breathes better for a year.
- Aerate. On compacted areas (paths, goal mouths, under washing lines) drive a garden fork 10 cm deep every 10–15 cm and rock it, or use a hollow-tine aerator on heavy clay and brush sharp sand into the holes. Compaction is the root cause of most moss and drainage problems.
- Overseed. Sow grass seed over thin and scarified areas at about 25–35 g per square metre, choosing a shade-tolerant mix where trees overhang. Keep it moist; germination takes one to three weeks while the soil is still warm.
October and November: autumn feed and leaves
Apply an autumn lawn feed — low in nitrogen, higher in potassium and phosphate — in September or October. Spring feeds push soft leafy growth; used now, that soft growth would be flattened by frost and disease. The autumn formulation instead hardens the grass and builds roots for winter. It is a genuinely different product, not a marketing distinction, so check the bag.
Rake or mow up fallen leaves weekly; a wet leaf blanket left until December kills the grass beneath it and shelters moss. The gathered leaves make excellent leafmould. Make the last cut of the year on a dry day, usually late October or November, with the blades set high, and then clean and store the mower.
December: rest, plan, and read the moss
Stay off frost and sodden ground, as in January. Winter is also the time to think about moss honestly, because moss is a symptom, not a disease. It colonises where grass is weak, and each situation points to its cause:
- Shade — under trees and on north-facing strips. Fix: raise the mowing height there, overseed with shade-tolerant fescues, thin overhanging branches, or accept moss and stop fighting.
- Compaction and poor drainage — moss in dips and along walked routes. Fix: autumn aeration, sand on heavy soil, re-levelling hollows.
- Scalping and acidity — moss across a lawn that is mown too short or very acidic. Fix: raise the blades; on confirmed acid soil a light lime application can help, but test with a cheap pH kit first rather than guessing.
Moss killers (usually ferrous sulphate based) blacken the moss so you can rake it out, but if the underlying cause remains, the moss returns by the following winter. Treat the cause in September, and the chemical becomes largely unnecessary.
The year at a glance
| Month | Key jobs |
|---|---|
| Jan–Feb | Keep off frozen/wet grass; service mower; clear debris |
| March | First cut on highest setting; re-cut edges |
| April | Spring feed; patch repairs; begin regular mowing |
| May–June | Weekly mowing at 2.5–4 cm; one-third rule |
| July–Aug | Raise blades in drought; do not water established lawns; no feeding in dry heat |
| September | Scarify, aerate, overseed; autumn feed from now |
| Oct–Nov | Autumn low-nitrogen feed if not done; clear leaves weekly; last high cut |
| December | Rest the lawn; diagnose moss causes; plan repairs |
None of this requires perfection. A lawn cut a little too long, fed twice a year at the right times and renovated most Septembers will outperform one that is scalped weekly and rescued with products in between.
Sources and further reading
- Royal Horticultural Society — lawn maintenance calendars, moss and thatch guidance, and drought advice.
- Met Office — seasonal outlooks, frost dates and rainfall data to help time first cuts and autumn work.
- Garden Organic — managing lawns and lawn weeds without synthetic chemicals.