How to Cut Long Grass Without Ruining Your Lawn

In this article, I’ll explain how to cut long grass.

More importantly, I’ll show you how to do it without damaging your lawn.


How to Cut Long Grass

cutting long grass

There are many reasons why your grass grows longer than normal. The most common reason is going on holiday.

You get back and the grass seems to have shot up out of nowhere.

You might also choose to let the grass grow longer during autumn, heading into the winter so by the time spring rolls around, it’s quite high.

Whatever the reason, the best way to cut long grass is to do it gradually and often.

In order to do that in a way which won’t harm your lawn, you need to follow some golden rules;

  • Increase mowing frequency – If your lawn is long it’s because you haven’t cut the grass as often as it needed. While bringing the height of the grass to a more manageable level, mow more often. Every two to three days or so.
  • Cut the grass when it’s dryMowing wet grass can be a nightmare, especially when it’s long. Firstly, because it’s dangerous, especially when using an electric roller mower. Secondly, it’s not good for your lawn mower, it puts extra load on the motor, it can cause corrosion and it’s a pain to clean off. And thirdly, wet grass tends to tear instead of cut cleanly. This trauma can open the door for fungal disease to infect your lawn. So choose the best time to mow.

Cutting Long Grass, Step-by-Step

Let’s say you come back off holiday and before you left, the grass was cut to 4cm. However, while you’ve been away, it’s shot up to 12cm.

Now you want to get it down to your preferred height of 4cm as quickly as possible.

In order to do it in a way that won’t harm the grass, you’ll need to do it gradually.

Step 1:

Give your grass its first cut, remembering to stick to the rule of thirds and not cut away more than a third off the length.

So if the grass is 12cm high, you want to remove a maximum of 4cm. This will bring the height down to 8cm.

Then let the grass recover and grow by a centimetre or so it’s now 9cm high.

Step 2:

Cut the grass again, removing a maximum of a third of the length, which is 3cm.

This will bring the height down to 6cm.

Again, let the grass grow by a centimetre or so and get to 7cm high.

Step 3:

Cut the height by a third again which is roughly 2.5cm to bring the height down to around 4.5cm

Let it grow again to 5.5cm.

Step 4:

For this last cut, reduce the height by 1.5cm. This will bring the height of the grass down to your preferred level of 4cm.

In order to maintain it at this length, never let the grass grow taller than 5.5cm.

Mowing Flattened Grass

Flattened grass is usually the result of using a lawn mower with a rear roller set at a fairly high cutting height.

If you don’t regularly change the direction in which you mow, then over time, the grass gets flattened and grows at an angle. As a result, the mower just rolls right over the grass and doesn’t really cut it so it could be as long as 12cm, despite your mower being set to 4cm.

If your grass is flattened, rake the lawn to stand the grass up before mowing it.


How NOT to Cut Long Grass

The worst of cutting long grass is to just hack it all off at once.

Grass uses its leave to trap sunlight (in the same way as a solar panel) to power the process of photosynthesis and production of food.

Grass leaves also store this food as well as water which it uses in times of stress.

If you come along and cut it all off, you not only rob the grass of it’s stored food supply, you also take away its ability to produce more food.

This shocks the grass, often turning it brown and in some cases, can kill it.

As a result, the grass puts all of its (now limited) resources into repairing itself and growing new leaf. This comes at the expense of root development and lateral growth.

If you mow the lawn in this way on a regular basis, you’ll end up with a lawn with sparse, patchy grass and riddled with weeds and moss.


The Best Lawn Mower For Cutting Long Grass

best lawn mower for long grass

The best lawn mowers for cutting long grass are 4-wheeled rotary mowers.

Lawn mowers with any type of roller will flatten the grass which could result in long grass, despite the mower being set to mow short.

Even the best cylinder lawn mower will struggle with long grass for this very reason.

Mechanical push mowers with rollers require a lot of effort just to push through long grass and as many of them have rollers and cylinder blades, they’re not the best choice.

Robotic, automatic lawn mowers are useless for cutting long grass. That said, they’re perfect for preventing the grass from growing tall in the first place. All without any input from you. So if the grass has grown tall because you don’t like cutting it, consider investing in a robotic model.


In Conclusion

So that’s how to cut long grass.

It’s not difficult, it just means you need to mow little and often in the short term.

If the grass has flattened, rake the lawn prior to mowing to stand it up and use a 4-wheeled rotary mower.

I personally have a selection of lawn mowers for this very reason. That said, rotary mowers are very cheap to hire if you don’t own one.

About Tim Stephens

I'm a professional gardener with degrees in Horticulture & Landscape Gardening. I want to help you create the garden of your dreams. I want your garden to look like it’s maintained by a professional. As if I was there doing it all for you!

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