When To Cut New Grass For The First Time
Mowing new grass too soon can rip out young roots so wait for the right height and take only a little off.
The short answer
Cut new turf for the first time once it has rooted firmly and reached 5 to 6 cm, and wait until a newly seeded lawn reaches 7 to 8 cm. On that first cut, set the mower high and take off no more than about a fifth of the grass height, using a sharp blade on a mild, dry day, then clear the clippings and water the lawn.
The first mow of a new lawn is a satisfying moment, and it's tempting to get the mower out as soon as the grass looks a bit long. Cutting too early is one of the easiest ways to set a young lawn back, though, whether you've laid turf or sown seed.
New grass is still building its roots and blades. Mow it before it's ready and you stunt that growth, weaken the plants before they've stored enough energy and, on a seeded lawn, pull young seedlings straight out of the soil. A little patience now pays off with a thicker, greener lawn later in the year.
When Should You Cut New Grass?
We recommend waiting until new turf reaches 5 to 6 cm and a newly seeded lawn reaches 7 to 8 cm before cutting it for the first time. Grass that has grown to that height is rooting well and can take a light trim without damage.
Height is the starting point rather than the whole answer. Run through the checks below before you mow, then follow the advice for turf or seed further down.
Five Checks Before The First Cut
1. Look At How The Grass Is Growing
Healthy new grass has an even colour and dense coverage across the whole area. If some parts look thin, weak or sparse, give them longer, because mowing grass that hasn't established yet only holds it back.
2. Test That The Soil Is Firm
A new lawn sits on freshly prepared soil that's still loose. Walk across a corner, and if your feet sink or leave deep prints, the weight of a mower will rut it. Wait for the ground to settle and firm up first.
3. Pick A Mild And Dry Day
Wet or frosty grass bruises and tears, and running a mower over it compacts the soil. Very hot spells stress young grass and slow its recovery after a cut. Aim for a mild, dry day with temperatures between 14 and 24 degrees.
4. Pull Weeds By Hand
Hold off on chemical treatments until the new grass has a strong root system, as even selective lawn weed killers can harm grass that has only just established. Pull any weeds out by hand during these first weeks instead.
5. Sharpen The Mower Blade
A blunt blade rips grass rather than slicing it, leaving ragged tips that turn brown. On a seeded lawn it does more damage, because the roots are weak enough to be torn out. Sharpen or replace the blade before the first cut, which our guide to servicing a petrol lawnmower shows step by step.
Cutting New Turf For The First Time
Before you mow, tug gently on the grass in a few places. Turf that lifts hasn't knitted into the soil yet, so leave it another week and test again, and once it holds firm, it's ready.
Set the mower high and take off no more than about a fifth of the height, which brings 5 to 6 cm turf down to roughly 4 to 5 cm. Rake up or box the clippings, then water the lawn with a hose or a garden sprinkler. For everything else in those early weeks, our guide to looking after new turf covers watering, feeding and keeping off it.
Cutting A Newly Seeded Lawn
Seeded grass needs to send up more shoots from its base and thicken before its first cut, which is why it should be taller than turf. How quickly that happens depends on the grass seed blend you've sown and the weather. Most seed starts to sprout within about 10 days, and the lawn is ready for its first cut from around 20 to 30 days, once it reaches 7 to 8 cm. Our guide on how long grass seed takes to grow goes into the timings in more detail.
Use the highest setting on your mower and again take off no more than a fifth, which leaves the grass at around 6 cm. Lower the height gradually over the next few cuts rather than all at once, and clear the clippings and water the lawn afterwards.
Our Tips For Cutting New Grass
- Take no more than a fifth off the height on the first cut
- Mow little and regularly rather than letting it grow long between cuts
- Keep the mower blade sharp so it slices instead of tearing
- Avoid mowing when the grass is wet, frosty or baking hot
- Change your mowing direction each time to stop the grass leaning one way
- Pull weeds out by hand and leave strong chemicals until the lawn is established
- Wait for the right height even when the lawn starts to look untidy
Mowing New Grass After The First Cut
Keep mowing regularly, taking only a little each time, and never remove more than a third of the height in one go, even once the lawn has established. Switching direction every time you mow stops the grass leaning and keeps growth even. Once the lawn has had a couple of months to settle in, a feed helps to strengthen the roots.
If you laid new turf, wait for 5 to 6 cm and a firm tug test before the first mow. Sown seed needs longer for its roots to take hold, so give it until 7 to 8 cm. Either way, a high first cut with a sharp blade on a dry day gets the new lawn off to the best start.
What People Also Ask Us
How long after laying turf can you mow it?
You can mow new turf once it has rooted into the soil and grown to 5 to 6 cm, which takes a few weeks after laying. Tug the grass gently before cutting. If the turf lifts, wait another week, and if it holds firm, set the mower high and take no more than a fifth of the height off.
Should you cut new grass short?
No, keep new grass long for its first few cuts. Take no more than about a fifth off on the first mow, then lower the height gradually over later cuts. Cutting new grass short stresses the young plants, weakens the roots and leaves gaps where weeds and moss can move in.
Should you collect the clippings after the first cut?
Yes, collect or rake up the clippings after the first cut of new grass. A layer of clippings left on a young lawn blocks light and holds moisture against the grass, which leads to yellow patches. Use the grass box if your mower has one, then water the lawn once you've finished.
Can you mow new grass when it's wet?
Avoid mowing new grass when it's wet. Damp grass tears rather than cutting cleanly, the mower deck clogs, and the wheels compact the soft soil and can pull young seedlings out. Wait for a mild, dry day once any morning dew has dried off the lawn.
What if my new lawn has thin patches when I planned to mow?
Hold off until they've filled in. A lawn that's ready to mow looks evenly green and dense all over, and thin patches are a sign that part of it is still establishing. Running the mower over them now only slows them down, so let the weakest areas catch up before that first cut.
Why does seeded grass need to be taller than turf before the first cut?
Turf arrives as mature grass on an established root mat, while seedlings are starting from scratch. They need time to send up more shoots from the base and thicken, and their shallow roots mean a mower can pull them straight out of the soil. That's why seed waits until 7 to 8 cm, against 5 to 6 cm for turf.
Does it matter which way I mow new grass?
Yes, a little. Mowing the same way every time trains the grass to lean in that direction, so switch it up from one cut to the next to keep growth even and upright. Direction matters less than height, though, and even an established lawn shouldn't lose more than a third of its height in one go.
Why does a blunt blade matter on a new lawn?
Instead of slicing the grass cleanly, a blunt blade tears it, and the ragged tips turn brown. That's bad enough on turf, but on a seeded lawn the pull can rip young plants out by their weak roots. A fresh edge before the first cut avoids both, and our guide to servicing a petrol lawnmower covers sharpening.
Archie is our gardening specialist. He started out as an apprentice at a gardening firm, built up his own knowledge from there and now writes most of our garden content.