How short should you mow your lawn? Cutting it too short risks bare patches and invites weeds to join the party. Cut it too long, and your lawn will look like an unkempt jungle, and you'll soon need a machete instead of a mower. The optimal cutting height depends on the type of grass, the season, and its condition. It's worth taking a close look before you just start mowing.
In the following sections, you will learn how short the lawn should really be cut. This will keep it healthy, lush green, and prevent it from growing out of control.
Contents
How to mow the lawn correctly: What grass height is suitable for which type of grass?
Not every type of grass in Germany requires the same cutting technique. Depending on the type of grass, such as perennial ryegrass, red fescue, or Kentucky bluegrass, the requirements for cutting height differ significantly. Only at the correct height will the lawn remain healthy and resilient.
If the grass gets too long, it becomes matted and the turf weakens, which promotes disease and weeds. Therefore, it's important not to miss the right time to mow. As soon as the grass exceeds the recommended maximum height, it should be cut. Below you will find a table with the recommended cutting heights before and after mowing for the most common grass types in Germany.
| grass species | When to cut? | Recommended cutting height |
|---|---|---|
| Perennial ryegrass (Lolium perenne) | From about 8–10 cm | 3–5 cm |
| Red fescue (Festuca rubra) | From about 7–9 cm | 3–4 cm |
| Kentucky bluegrass (Poa pratensis) | From about 8–10 cm | 3–5 cm |
| Bluegrass (Poa spp.) | From about 7–9 cm | 3–4 cm |
| Lagerspe (Poa supina) | From about 6–8 cm | 2.5–4 cm |
How short to mow the lawn throughout the year
The correct lawn cutting technique changes throughout the year. For example, grass needs more length in spring, while a shorter cut helps with heat protection in summer. Below you will find information on how to optimally adjust the cutting height depending on the season.
How short to mow the lawn in spring
For the first lawn cut in spring, the unforgiving rule is: shorter than in summer, but never scalp it. Set your mower to 3 to 3.5 cm to radically remove winter damage and diseased tips, forcing the grass into a dense growth spurt. This strategic wake-up call brings light and air to the turf and combats moss, but strictly adhere to the rule of thirds: if the lawn is too high, mow in stages over several days. After the first few cuts, gradually raise the height back to the robust summer ideal of 4 cm to lay the foundation for a dominant, weed-free lawn.
How short to mow the lawn in summer
In summer, mowing your lawn too short is a cardinal sin against it. Increase the cutting height to at least 4 cm, and even 5 cm in extreme heat. Every extra millimeter of grass acts like a natural sunshade for the soil: it protects the sensitive roots from burning, drastically reduces water evaporation, and suppresses weed growth. Those who mow their lawns short in summer reap nothing but a straw-like, brown, and stressed patch. Longer grass is your best and cheapest insurance against the scorching summer sun.
How short to mow the lawn in autumn or before winter
The last lawn cut in autumn isn't just a formality, but crucial preparation for winter. Set the cutting height to about 5 centimeters. This is the ideal middle ground. Cutting it shorter deprives the grass of its natural frost protection. Leaving it longer promotes rot and fungal diseases under the snow. Be sure to remove any fallen leaves when mowing, as only a clean lawn will survive the winter healthy.
How to cut your lawn correctly: ideal cutting height for every situation
The perfect lawn cut depends not only on the season but also on the specific situation. Whether it's scarifying, weeds, heat, or rain, every challenge demands the appropriate cutting height. Incorrect mowing weakens the lawn. Below you will find the most important rules for the ideal cut.
1. Scarifying the lawn: How short should it be mowed?
There's no mercy before scarifying. This is surgery on the heart of your lawn, not a gentle trim. Mow the lawn to its lowest setting, ideally 2 cm. This allows you to target thatch and moss without damaging healthy blades of grass. A longer cut would simply shred the soil instead of aerating it. The short cut provides unobstructed access and makes the process effective. Only then can the scarifier work properly.
2. Should I mow the lawn short to suppress weeds?
This is one of the most fatal myths about lawn care. Anyone who believes that short mowing will combat weeds is actually actively encouraging them. Cutting the grass to 2-3 cm practically invites dandelions and clover. They weaken the lawn, reduce the leaf mass available for photosynthesis, and thin out the turf. This allows light to reach the soil unhindered, stimulating weed seeds. The best weapon against weeds is a dense lawn with a height of 4 to 5 cm. This dense grass cover blocks the light and smothers the weeds before they even sprout.
3. How short should the lawn be mowed before a long heat wave?
Cutting your lawn short before a heat wave isn't just a minor mistake, it's a death sentence. Increase the cutting height to at least 5 cm or more. Every millimeter of grass blade acts like a sunshade, cooling the soil and reducing water evaporation by up to 50%. This protects the roots from burning. Short-cut lawns lie unprotected in the sun, the soil heats up, water evaporates quickly, and the roots die. A high cut is the best and cheapest way to protect against heat stress.
4. Should you mow the lawn just before it rains?
This is a professional strategy, provided the timing is right. Mow the lawn to about 4 cm while it's dry. The subsequent rain will wash the mulch into the turf, where it acts as fertilizer. At the same time, it provides the freshly cut grass with water for quick regeneration. It's important that the mowing is finished before the first drop of rain. Mowing wet grass is a mistake; it clumps, tears unevenly, and promotes fungal diseases.
5. How short should the lawn be mowed before fertilizing?
Spreading fertilizer on a jungle-like lawn is a waste of money and resources. Mow the lawn to a height of 3.5 to 4 cm one to two days before fertilizing. This allows the fertilizer to fall freely to the ground. If the grass is too long, a lot of fertilizer gets caught in the blades and, in damp conditions, can burn the leaves instead of reaching the roots. A freshly mowed lawn, not too short, ensures that the fertilizer works exactly where it's needed: at the base, ready for root absorption.
How short exactly? The golden rule for mowing the lawn.
The optimal cutting height varies depending on the season and the condition of the lawn. So, is there a golden rule? The experts at Segway Navimow have developed a universal plan for those who want simplicity, and it almost always works.
The golden rule: 4 centimeters. Set your mower to a cutting height of 3.5 to 4 cm. This is the standard for around 90 percent of German gardens. In the height of summer, increase the cutting height to 4.5 cm or more. Cutting the lawn down to 2 cm invites weeds and moss and risks burning the roots in the heat. A higher cut promotes a deep root system that better withstands drought and ensures a dense lawn that smothers weeds.
The one-third rule is your inviolable law. Never cut more than one-third of the grass height at a time. Your goal is 4 cm? Then mow at 6 cm at the latest. Letting the grass grow wild for a week and then cutting it drastically puts the lawn under massive stress, leading to yellow patches and disease.
Fire the gardener and get a robotic lawnmower! Who has time to mow three times a week in May? Nobody. A robotic lawnmower isn't a luxury, but the smartest tool for a perfect lawn. The Segway Navimow i105, in particular, works precisely according to the rule of thirds, as it only trims the tips daily. This constant, small cut ensures a dense lawn. It also distributes the fine clippings as natural fertilizer, improving the soil and reducing the need for artificial fertilizers.
Mulching is an effective way to recycle nutrients. The clippings should ideally remain on the lawn. A robotic or mulching mower finely chops the grass blades so they fall into the turf, where they are decomposed by microorganisms and provide the soil with valuable nutrients. This reduces the need for fertilizer, but doesn't eliminate it entirely. It's important to note: If the grass is too long or wet, the clippings must be removed; otherwise, rot and fungal diseases can develop.
Summary
How short is the optimal cutting height, really? The answer is both simple and complex. You need to know the type of grass, the season, and the condition of your lawn precisely to determine the right time and the appropriate cutting height. For beginners and those who prefer convenience, there's a golden rule that almost always works. Modern robotic lawnmowers like the Segway Navimow i series make life even easier. Simply set the desired cutting height via the app, and the robot will independently ensure perfect and efficient lawn care across the entire area.
Follow these principles and your lawn won't just survive, it will dominate. Dense, green, and resilient. Anything else is a pure waste of time and money.
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