Cutting grass too short is the most common lawn care mistake most gardeners make.

Letting grass grow tall and then mowing it all off in one go has a negative impact on the health and appearance of your lawn.

If you mow your lawn short and you find it’s thin or patchy and full of weeds, then you are likely to be the cause of the problem.

To create and maintain an attractive, thick, green, healthy lawn, you need to understand what the grass plant is and how it works.

Caring for it then becomes easy and you’ll be able to create a lawn which is the envy of the neighbourhood.

Two Misguided Reasons for Close Mowing

People mow their lawns very short for one of two reasons;

  • To avoid not have to mow as often
  • To try and make their lawn look like a professional putting green

We’ll address each problem individually.

To Not Have to Mow as Often

If you don’t like gardening, then I understand the temptation to mow your lawn every two weeks (or even less) instead of once a week. This may well save you a couple of hours a month, but it will be detrimental to the health of your garden over time.

To Make Your Lawn Look Like a Putting Green

Who doesn’t want a lawn that looks like a famous putting green?

Some gardeners try to achieve this look by mowing very short.

This is not how it should be done.

A Quick Educational Lesson on Grass

To understand why having a lawn that’s too short is not good for your grass or the rest of your garden, you need to know how this plant works. You will then understand why this can create a range of problems.

A Grass Leaf is Like a Solar Panel

Solar panels on the roof of your house can produce electricity. To achieve this, they need to get as much sunlight as possible which means placing them facing on roofs.

North facing or shaded areas won’t be able to produce a lot of energy because they don’t receive as much direct sunlight.

The same concept applies to grass but instead of producing electric power, plants produce energy through photosynthesis where sunlight is turned into food through photophosphorylation (using water and plant nutrients).

Bigger grass leaves are better since they have a larger surface area that allows for absorbing more photons (light particles).

In simple terms, the longer your grass, the better it can feed itself. Short grass can’t feed itself as well which will lead to the plant having to sacrifice root development for growth.

Grass Leaves Also Store Food and Energy

Grasses are incredible plants. One of their most underrated features? They store water, carbohydrates, and proteins to use when it’s needed. For example, in hot summers or during a cold winter frost, grass uses these stored reserves for survival.

What Happens When You Cut Grass Too Short?

When you cut the grass too short you cause several problems. Each problem having a causational effect causing another.

You Take Away the Grasses Stored Food Supply

As you know, grass stores food in it leaves for times of drought or stress.

When you mow your lawn too short, you take that food supply away. This is even worse in the summer months when the grass needs that supply of food to survive the hot and dry weather conditions.

You Reduce its Ability to Produce More Food

Your grass is not only deprived of food and sunlight but also its ability to produce more.

If this doesn’t kill the plant, it deprives it of essential resources that should be spent on root development and focuses on repair and growth instead.

Intolerance to Drought

As the grass has now sacrificed root development to produce new leaves, the roots don’t grow as deeply. Instead, these roots stay in the upper layers of the soil.

When it gets hot, the sun dries the earth and any moisture left evaporates. This removes all access to water which means the plant is unable to consume nutrients from the soil.

The grass then becomes dormant and may even die.

Weed Moss and Disease Takeover

If your grass manages to survive, it will be weak and patchy.

This causes weeds, moss, and disease to take over which will completely ruin your lawn. The grass simply isn’t dense or strong enough to fight these infestations.

What About Golf Courses and Bowling Greens?

Greenkeepers can keep bowling greens and golf courses in pristine condition when the grass is only 6 mm long. This may sound difficult, but it’s actually due to a few key factors.

Firstly, these types of surfaces have strict maintenance regimes which enable the grass to survive at such a short height. They use slow-growing bent grass varieties rather than common lawn species like rye or fescue (which would never withstand short mowing).

The other factor to consider is the type of lawn mower used. Instead of an ordinary rotary blade machine with really high blades for cutting down tall weeds and plants on normal gardens, greenkeepers use advanced cylinder machines designed specifically for maintaining neat turf where there are no weeds present.

Grass clippings are also mulched back into the lawn in conjunction with a strict watering and lawn feeding regime.

Can I Not Have a Putting Green Lawn?

Yes, you can.

It will require a lot of time, effort and knowledge to create and maintain this type of lawn.

You’ll need to choose the very best grass seed you find. You’ll also need to invest in the best cylinder mower you can afford.

If you’re not an avid gardener, trying to achieve a golf course lawn isn’t the best idea.

So How High Should You Cut the Grass?

I’ve answered this question in more detail in this article: How High Should I Cut My Grass?

But the simple answer is…

It Always Depends

Lawn mowing is a compromise between achieving a uniformed lawn and keeping the grass healthy.

The best height for mowing depends on many factors: season, environment, and the type of grass. During spring or autumn when growth rate is high you cut more frequently.

During summer or winter less frequent cutting leads to taller turf which retains its leaf canopy with all those nutrients needed throughout the colder months

If you use a lawn mower with a roller, the height of the grass also affects how visible the striped finish is. The shorter the grass, the less bold the finish will be.

A General Rule of Thumb

The general rule is to never remove more than a third of the grass leaf at a time.

If your grass is 6 cm tall, only cut a maximum of 2 cm off the height to bring it down to 4 cm. Then when it grows to 5 cm, reduce the height by 1.5 cm to bring the height down to 3.5 cm.

Even when cutting long grass, bringing the height down gradually by only removing a maximum of a third of the leaf at a time, will ensure the grass remains healthy.

For most homeowners, lawns look their best when they’re between 3 cm – 6 cm high.

Learn more: When to Cut the Grass.

Final Verdict

There’s more to mowing the lawn than many people think.

Grass leaves need to be treated properly for them to reward you with an attractive lawn.

You might have a good lawn mower, but if you don’t cut the grass properly by cutting too short, you’ll ruin your lawn.