What is the ideal cutting height for a robotic lawnmower?

The question of the ideal cutting height for a lawn drives many garden owners crazy. And yet it cannot be answered definitively because not all lawn types are the same. There are even special rules that apply in summer heat. This makes it all the more important to take the required flexibility into account when buying a robotic lawnmower.

Elegant ornamental lawns or robust commercial lawns, dry summer periods or the first cut after winter: there are many factors that influence the ideal cutting height of the lawn. Unfortunately, it is not always consistent after you have decided on a lawn type. In order to be prepared for all these situations, it seems quite reasonable to attach importance to maximum flexibility when buying the robotic lawnmower.

Adjusting the cutting height of the robotic lawnmower

The adjustment of the cutting height is not much different from that of a conventional lawn mower. Sometimes an adjustment knob is located under the cover, sometimes on the side or on the bottom of the device. With some robotic mowers, the cutting height can also be conveniently adjusted via a display. The manufacturer's instructions will tell you where to find the cutting height setting on your model. 
The cutting height is adjusted either in steps or progressively. Manufacturers usually specify the minimum and maximum cutting height here. The larger the range, the more flexible your robotic lawnmower. 

Often, many robotic lawnmowers only have a cutting height between 20 and 60 millimeters and are not necessarily suitable for shade lawns. Other models have a range between 20 and 100 millimeters, offer maximum flexibility during any season and work for any type of lawn. However, no robot on the market mows a lawn shorter than 15 millimeters.

Since frequent mowing by the robotic mower can slightly weaken a law, ideally a cutting length from 30-40 millimeters is recommended in practice.

Pendulum suspended mowing deck - perfect cutting results

Most ground areas are not completely level. A rigid mowing deck cannot follow the contours of the surface, so the lawn is not the same length everywhere. A robotic lawnmower with a pendulum-mounted cutting deck always follows the surface leaving the lawn evenly cut everywhere and is characterized by a perfect cutting pattern.

Which cutting height for which type of lawn?

In most gardens, a lawn should not only look fantastic, but it is also used for playing, sunbathing or barbecuing. Accordingly, at the time of sowing, choose a durable, robust commercial or play lawn. In order to avoid additional strain on your lawn, cutting heights of 35-55 millimeters are recommended. A lush green ornamental lawn, on the other hand, is characterized by its dense growth and fine grass blades. The green is only suitable for loading to a limited extent, as it is much more sensitive than a commercial lawn. Thus, the blades can tolerate extremely low cutting depths starting at 2 centimeters. Please note: let the lawn grow longer during dry periods. Otherwise the blades will turn brown very quickly. Ornamental lawns especially should be watered correctly.

Shade lawns are another type and should be kept particularly long with a cutting length of around 60 to 70 millimeters. This will ensure that photosynthesis takes place on leaf surface of the blades.

Special cutting heights for special occasions

In principle, the type of lawn serves as a good guideline for the choice of cutting height. However, there are always situations that require exceptions to this basic rule.

  • Before dethatching, mow the lawn as low as possible, i.e. even commercial lawns may be cut down to 2 centimeters.
  • During prolonged droughts in summer, lawns develop a natural protective layer to prevent excessive drying. You should not destroy this layer by excessively mowing your lawn. This practice will simultaneously protect the soil from drying out even more. Moreover, choose a longer cutting length during this period.
  • Cut the lawn back to about 40 to 50 millimeters during the last cut of fall/autumn. This way, the blades will not bend under the weight of snow in the winter.
  • In spring, the lawn starts to grow when temperatures rise. Wait with the first cut until temperatures are permanently around 10°C or above. Then cut off no more than 1/3 of the blade length. The gradually work your way to the desired length.
  • Freshly seeded lawns should first grow to a length of about 8-10 centimeters before you can mow them directly down to 5 centimeters.

Avoiding the wrong cutting height

Cutting the lawn too low or too high will inhibit its growth. 

  • If the blades grow too high and are cut infrequently, fewer side shoots will form. The lawn will then become less dense. Furthermore, there will be more room for weeds and moss to grow, which can spread particularly quickly.
  • If cut too deeply, too much sunlight will reach the soil surface. Not only does this cause the soil to dry out faster, but it also encourages weed growth.

Regular cutting is therefore important and ideal for the use of a robotic mower.

If necessary, adjust the cutting intervals to the growth rate of the lawn. In spring, for example, lawns grow much faster than during a dry summer. From early to mid-November, on the other hand, the lawn hibernates and should not be mowed at all.

1/3 rule for a healthy lawn

No matter how long the lawn is after vacations or winter breaks, it's important that you remove no more than 1/3 of the blade length per mowing. If you go beyond that, grass clippings will remove too many nutrients from, and it will become more susceptible to disease.

There is no one ideal cutting height for lawns, but there is a perfect robotic lawnmower for all cutting heights. When buying, choose a model that offers maximum flexibility for every occasion so you can give your lawn what it needs in every situation.