When the grass is growing and the ground is firm enough to walk on without marking it — and at the highest setting the machine has. Not on a date.
Why the timing is a judgement
Two things have to be true. The lawn has to be actively growing, so that what you cut regrows rather than sitting as a wound. And the ground has to have dried enough to carry a mower without taking wheel ruts.
In a mild year those conditions arrive weeks earlier than in a cold one, and there is no calendar date that captures it.
Why it takes two passes
Because a lawn that has stood all winter is far more than a third above your summer height, and the one-third rule applies here more than anywhere. Cutting straight back to 35 mm in March removes most of the leaf at the moment the plant needs it to start.
Do it in two: the first pass at the highest setting the machine offers, and the second three to seven days later a step lower. On a badly overgrown lawn, three passes.
What the machine is up against
This is the hardest work a mower does. The grass is long, often damp, and frequently laid flat in patches. A cordless machine will use a great deal more energy than its stated area implies. A petrol machine will want a clean air filter and fresh fuel rather than what has been in the tank since October.
Expect the catcher to fill quickly and the deck to pack. Both are normal at this one mow and not at any other.
What to do before it
Walk the lawn and pick up what the winter left — twigs, stones, a forgotten peg. A stone through a plastic deck is a mower gone; a stone through a boundary wire is an afternoon.
And check the blade. A season-old blade that was dull in October has not improved, and the first cut is the pass where it matters most.
How this site handles it
The blade family and the mower service parts here — air filters, wheels, catchers — are the shelves this one mow tends to send people to. Their pages print what the maker states about fit, because a part that does not fit is the reason a first cut gets postponed another week.
The questions that keep coming in
Should I collect the clippings on the first cut?
Yes. There is more material than a mulching deck can disperse, and left on the surface it mats and smothers the grass underneath at exactly the point it is starting to grow.
My mower struggles badly on the first cut. Is it undersized?
Not necessarily. The first cut is the hardest work the machine does all year, and every figure on its listing — runtime, stated area — was derived from conditions nothing like it. Two passes at a higher setting is the fix.
Last reviewed 26 September 2026