Does Cutting New Grass Help it to Grow?

Lawns, when cared for properly, can become the envy of the neighbourhood. If you’ve just set up your new lawn, or are thinking to, you may be wondering if mowing new grass helps it to grow?

Cutting new grass can help it to grow, but only if you do it correctly and at the right time. You need to wait long enough for your grass to take root before mowing it and don’t cut more than 1/3 of the leaf height. Then you’ll be helping your new grass to grow thick and healthy.

However, when cutting your new lawn, it can be a fine line between help and harm. What are the things you need to know before you start mowing?

Read on to learn when, and how to make your first cut.

How Mowing New Grass Promotes Growth

Grass uses a process called photosynthesis. This is when the plant turns sunlight into the nutrients the plant needs. Because of this, your new grass needs the sun to grow (and the big reason why grass doesn’t grow too well in the shade).

As the grass grows taller, you may notice that some bits grow faster and are taller than others. The taller blades block the sunlight to the shorter ones. By mowing regularly, you keep the leaves at the same height, so that they all have access to the sun, and grow evenly.

There is another reason why mowing new lawn promotes growth. When you prevent the grass from growing vertically (skywards), it converts that energy into growing horizontally (along the ground).

The end result is thicker grass. This is why mowing new grass frequently helps it to grow from patchy little tufts to even coverage in a shorter space of time. Thicker grass will also make it harder for any weeds to grow!

Should I Mow My New Grass Short?

You might be thinking: “well if keeping it short makes it grow thicker, the shorter it is, the faster it’ll spread”. Hold on! It doesn’t quite work that way.

Grass has a minimum height that it needs to be to stay healthy. If you cut it too short, or cut too much off at once, you can harm it health. This is called scalping your lawn. 

What does scalping mean? Read on!

Does scalping kill grass?

Scalping your lawn places extra stress on the plant and will slow down growth as it will put its energy into recovery, not growth. Scalping causes damage to an established lawn, but to a new one, it can be devastating.  

Never cut more than 1/3 of the total height off the leaves when you mow, and its minimum height should be 2.5-3cm.

If you cut your new lawn so low that go past the green leaf blades and into the stems this is called “scalping.” And it’s something you’ll want to avoid as your lawn needs its leaves to turn sunlight into nutrients.

The extra stress on your grass leaves your lawn less capable of handling drought and gives weeds a chance to grow through.

Now that you know how mowing improves lawn growth, (and the risk of scalping), read on to learn when, and how to make your first cut.

The first cut of a new lawn

You’ve started a new lawn and are starting to see some growth, so now comes the question: when do you make the first cut?

When to mow grass for the first time

To work out the best time to mow your new grass for the first time you need to consider how you planted it. The main thing you want to look at is the strength of the grass blades if you grew your lawn from seed. Are they still very fine, or do they have some width? And for turf, whether the roots have established.

New grass takes time to establish a root system strong enough to secure it. Until then, walking on it is enough to cause damage, so trundling a mower over it can leave wheel tracks of torn out grass, especially when turning. (Which is not what you want when spending the time and money to grow a beautiful new green lawn).  

You’ll also want to let it grow a little higher than usual before the first cut, around 6cm. When you mow, only take it down to about 4cm, following the 1/3 rule (never cut more than 1/3 of the total height off. No scalping!).

Keep your mowing to this height weekly for the next few weeks, before trimming it down to your grass species recommended height (generally around 2.5-3cm).

When to mow new turf

You’ll generally need to wait 3-4 weeks after laying turf for the roots to take hold. Before mowing, give the corners of the lawn a light tug to make sure it’s secure.

Another thing to note is that the soil where the turf is laid should be kept moist until the roots are established. But soft damp soil is not suitable for mowing (especially new roots). Turn off any watering you have set up 48 hours before your first mow to give the ground a chance to dry. 

Mowing new grass seed

Growing a lawn from new grass seed is a waiting game; it may take up to 2 months before it’s ready for mowing.

The important thing is to be patient. Mowing too soon can uproot your newly sprouted grass, and the new shoots don’t yet have the strength to withstand the mower blade. Newly seeded lawn also needs to be kept moist while it establishes.

You can see in this picture below, each blade of newly seeded grass is way too fine to cope a hit with the mower. Let the leaves broaden and get stronger, before you walk on them or mow them.

When can you cut new grass seed?

As with the turf, stop all watering to the lawn 48 hours before the first mow, giving it a chance to dry.

Can I mow after overseeding?

If you have a damaged or patchy lawn, one of the simplest ways to fix it is to use overseeding. Give the new seed as much time as you can to establish before you mow. At least 7-10 days, depending on how quickly it’s growing. Don’t cut more than ⅓ of the height of your grass off.

I’d recommend mowing before overseeding, this will give your newly planted seed the longest time before it needs to face the mower for the first time.

Simply sow new seeds into the areas you want to be thickened (or the whole yard if it’s a bit thin), water and wait for it to grow.

Will mowing and overseeded lawn damage the new grass? 

While a fully seeded new lawn takes 2 months to be ready for the first mow, you don’t have to wait as long with an overseeded lawn. This is because the established grass helps to support and protect the new seedling for their first mowing.

You should still give them as much time to grow as you can, but if you let the existing grass get too long, it’s leaves will overshadow the new seedlings. Without the sunlight that they need, they can’t make nutrients, stunting their growth. So the best balance is to mow 7-10 days after overseeding and leave it another 7-10 days before your second mow.

If there are whole patches of your yard that only has new seedlings (there is no established lawn there), then mow around them for the first 2 months, and hand trim any longer strands of the original grass.

Frequent FAQs

When can I cut my new turf?

After laying turf you need it to establish it’s roots into your soil before cutting it for the first time. Generally, this takes 3-4 weeks, depending on the season.

How long after sowing grass seed can you mow?

Grass seed when it first sprouts has very fine and delicate grass blades and shallow root systems. You need to wait until your grass is established, which may take up to 2 months depending on the season.

Will grass thicken on its own?

Grass will thicken on it’s own if you maintain it properly. Keeping it at a height of 3-5cm and ensuring that you do not cut more than 1/3 of the leaf height at any time. Allowing the grass to seed, can actually thin your lawn.

Now you know how to cut new grass to help it grow. If you need any mowers, just remember here at our Canberra Mower centre in Mitchell, we are the local Husqvarna dealer with the best quality lawn mowers in town.

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