There is no single right date

Ask five meadow-makers when to cut and you will get five answers, all of them defensible. That is because cutting is not a date on a calendar so much as a response to what is actually growing in front of you. A hay meadow on thin chalk downland, a damp rushy field in the Welsh borders and a suburban lawn-turned-meadow in Sheffield will each want something different. The traditional late-July hay cut is a useful starting point, not a rule. Getting it roughly right is far better than waiting for perfect information, and the consequences of being a fortnight early or late are usually modest.

Read your ground before you set a date

Soil fertility drives everything. On rich, previously improved ground, grasses such as cocksfoot and Yorkshire fog will race ahead, flop over and smother your flowers. Here, cut earlier and cut more often — a first cut in late June or early July, with a second in September, will do more for diversity than any amount of seed sowing. On thin, undisturbed soil, growth is slower and one late cut is plenty.

Location matters too. A sheltered meadow in Devon can be a fortnight ahead of one at 300 metres in the Pennines, and a north-facing slope will lag behind a sunny south-facing one. So walk your ground and look for the signals rather than watching the calendar:

• Ox-eye daisies and knapweed are shedding petals and setting seed
• Yellow rattle pods rattle when you shake them
• Grass seed heads are ripening but the stems have not yet collapsed
• Meadow browns and ringlets are on the wing rather than emerging

When most of those boxes are ticked, you are in the window.

Why the traditional late-July hay cut works

By late July, the great majority of meadow wildflowers have flowered, been visited by insects and set seed. Cutting then lets that seed fall into an opening sward, while removing the year's growth takes nutrients out of the system and keeps the grasses from swamping everything. The classic pattern of a hay cut followed by aftermath grazing in late summer and autumn is what created Britain's flower-rich meadows in the first place.

Cut in June and you lose the seed crop, remove nectar before the bees have finished with it, and risk disturbing ground-nesting birds and the larvae of butterflies that overwinter low in the grass. Cut in September and the grasses will have lodged, the flowers will be shaded out and you will have handed the advantage to the coarsest species.

Match the cut to the wildlife you want

This is where a meadow becomes a project rather than a chore. Decide what you are managing for, then let that shape the mowing:

• Bumblebees and butterflies: stagger your cuts. Leave 20–30 per cent of the meadow uncut each year and rotate which strip you leave, so there is always standing nectar and somewhere for larvae to sit out the winter.
• Ground-nesting birds: skylarks, meadow pipits and lapwings need cover well into July. Walk the field slowly before you cut, and if you find a nest, mow around it and come back later.
• Overwintering invertebrates and small mammals: leave tussocky grass standing through the winter and cut it in early spring instead. Frogs, shrews, hedgehogs and countless insects rely on that architecture.
• Seed-eating birds: linnets and goldfinches will strip knapweed and teasel heads in autumn, so leave some patches standing into November.

What to do with the cuttings

This is the part most people get wrong, and it undoes years of good timing. If cut grass is left lying, the nutrients go straight back into the soil and the meadow reverts to rank grass within a couple of seasons. Remove it. Rake it, bale it, compost it, use it as a mulch under hedges — anything but leave it in place.

Leave the cut material for two or three days so seed can drop, then clear it. Cut on a dry, mild day, work from the centre outwards so that any animals in the grass have somewhere to run, and go slowly. A flushing bar on the front of a mower, or simply walking ahead with a stick, saves a surprising number of casualties. Leave the very edges rough — a shaggy margin is worth more to wildlife than a tidy one.

Adjusting through the year and from year to year

Many meadows benefit from a light spring tidy in March or April, before growth really starts, to knock back the rankest grasses. Never do this on a meadow you are still establishing, and never cut a spring-flowering sward before the cowslips and early orchids have set seed.

If you keep livestock, autumn grazing does the job of a second cut beautifully, with the added benefit of uneven tussocks and bare patches for seed to settle into. If you do not, a second cut in September, cleared away, is the next best thing.

Finally, accept that every year is different. A wet, warm summer pushes growth on and may bring your cut forward; a cold spring delays it. Keep a brief note of what you cut, when, and what you saw flowering and flying. After three or four seasons you will have a schedule tailored to your own patch — which is far more valuable than any general advice.