How Low Should You Mow a Lawn? When to Cut Grass Short?

By   | Last Updated :   April 26, 2023 | Filed In :   DIY & How To

Eager to give your lawn a low cut? You may think you’re helping it, but it’s usually better to avoid mowing your lawn short.

Mowing your lawn too short can do more harm than good. For most types of grass, a cut at 2.5 to 3 inches through most of the year helps keep the grass strong and healthy. In general, warm-season grasses require a shorter cut while cold-season grasses need a longer one.

The only time to cut grass short is in preparation for winter, to prevent matting and disease. But even then, you don’t want to cut your grass lower than 1½ to 2 inches. 

Read on to find out more about the best grass height during the different times of the year.

how low should you mow

Image credit: @vermeersgardencentre

Is it better to cut grass short or long?

When you lower the mowing height, you sacrifice root depth. Cutting grass short makes the grass use nutrients to grow the blade above the ground instead of strengthening the roots. As a result, the grass becomes fragile. More than being easily damaged, it can be pulled up by the mower.

Longer grass provides the lawn with more protection against the sun and heat. It offers shade to the soil beneath, helping to retain moisture during the hotter days of the year. It also makes life easier for bees and other beneficial insects.

In short, a lawn with taller grass is a healthier, less stressed lawn.

How short can I cut my grass?

The ideal height for most types of grass is between 2.5 and 3 inches. This height shades the soil beneath the grass from the sun, helping to retain moisture. It can also help prevent weeds from developing by robbing them of sunlight.

Got a serious weed problem? Set your mower blades higher. Cutting grass at 3 to 4 inches will prevent the weeds from getting enough sunlight. It’s a natural way to help your grass blades outcompete weeds without resorting to weed killers.

Good to know: Never cut more than 1/3 of the leaf height or you may stress the lawn. If your lawn grass has grown very tall, use repeated cuts to reach an optimal height.

When to cut grass short?

You can mow your lawn down to 2 to 2.5 inches in late autumn, in anticipation of the first frost of the year.

More on this: When should you STOP mowing your lawn in UK? (last cut of the year)

This height enables the grass to resist colder temperatures. At the same time, it helps it withstand disease.

Certain warm-season grasses such as Bermuda grass and zoysia stay healthy when cut short. During the growing season, cut grass like Bermuda to 1 to 1½ inches and zoysia at 1½ to 3 inches.

With that in mind, it’s best to avoid close mowing. It can promote shallow rooting, weaken the grass, and make your lawn more susceptible to weeds, moss, and drought. It can even lead to scalping, which exposes the soil beneath the grass.

Important: Avoid mowing your lawn short in times of stress, such as during hot temperatures or dry spells. A low cut will put additional stress on the grass. Aim for a high cut instead.

when to cut grass short

Image credit: @fredchavezO

How short to cut grass in spring?

In spring, mow cool-season grasses to 3 inches and warm-season grasses between 1 and 1½ inches. Don’t cut the grass shorter than this as it will leave it vulnerable to weeds and the rising heat. Make sure to check your mower blade settings before putting the mower to work.

Tip: Mow shady areas ½ to 1 inch higher than sunny spots. Longer grass blades will better absorb sunlight.

You Might Also Like: Spring Lawn Feeding: When To Do It & Best Fertiliser

How short to cut grass in summer?

Cut cool-season grass between 3 to 4 inches and warm-season grass between 2 to 2.5 inches. A long cut in summer shades the grass roots from the heat and helps to prevent weeds. It also enables the grass to better withstand dry spells.

Cutting your grass shorter than that could leave it exposed to the heat. The soil will lose moisture faster and you’ll need to water it more often if it doesn’t rain.

Tip: Moss in your lawn? Make sure to mow the grass at least ½ an inch above the moss height. This will help promote the growth of the grass and hide the moss from sight.

How short to cut grass in autumn? Should you leave your grass long or short for winter?

Before winter, mow cool-season grass to about 2.5 inches and warm-season grass to 2 inches. Mowing grass shorter than this before the first frost can leave the grass roots exposed to cold temperatures, and this can damage them. Tall grass, on the other hand, can become tangled and prone to disease.

Tip: New lawn? New lawns need around nine months to grow mature roots. During this time, avoid giving them a low cut. Keep the cut high.

how short to cut grass in autumn

Image credit: @nozzlenolen

How to save grass that was cut too short?

Reduce the frequency of the cuts to enable the grass to grow back to a healthy height. Water it thoroughly and more often to encourage growth. When you next mow it, don’t cut more than 1/3.

Grass that was cut too short is exposed to more sunlight, which can damage its roots. It also struggles to hold moisture, making it dry out more quickly.

Don’t fertilise grass that was cut too short to speed up its growth. At best, it will force weak growth. At worst, it will simply burn the grass. It’s best to wait until after the grass recovers before fertilising. Check out our full guide on when to feed a lawn.

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