Global menu

The Green pages

Mowing the lawn

English
Lawn - Arboretum
Photo: Jardin botanique de Montréal (Lise Servant)  
Lawn - Arboretum

Mow high, mow often and leave the clippings on the ground

Mowing high promotes vigor, density and deep rooting for turf grass. This gives the lawn greater resistance to drought and makes it less vulnerable to pests, to diseases and to weed populations.

The ideal mowing height is about 7.5 centimeters. Only the first mowing in spring and the last one in fall should be shorter. Mowing your lawn to 5 cm at the start of the season will stimulate growth; at the end of the season, it will help prevent disease.

A little gesture for pollinators

You can lend bees and other pollinators a helping hand by putting off the first mowing of your lawn until the dandelions flower. That’s particularly useful when nothing else is blooming in early springtime. At that time of the year, sources of nectar and pollen for pollinating insects are hard to find.

But make sure to mow the lawn or eliminate inflorescences as soon as the first dandelion flowering is finished, before the production and scattering of seeds. Also ask your municipality or borough for what the regulations are regarding maximum lawn height or the presence of weeds on private land.

How often should a lawn be mown?

A lawn should be mown regularly, never removing more than one-third of the total blade length at a time. To keep the lawn at a height of 7.5 centimeters, mowing should take place when the grass is 11 to 12 centimeters long. This means that in periods of active growth, mowing should be done every week, even every five days. During the summer months, on the other hand, mowing once every two weeks is generally enough.

Should grass clippings be picked up?

With certain exceptions, there’s no need to pick up grass clippings. On the contrary, it’s beneficial to leave them on the ground so that the microorganisms in the soil can break them down, allowing them to release the nutrients they contain. This practice is called grasscycling. To speed up the decomposition process, use a mulching mower, or run a regular lawnmower over the clippings.

In the following situations, it is nevertheless recommended to pick up lawn clippings:

  • When weeds such as crabgrass have begun to form their seeds. If those plants haven`t been pulled up before seed production, it’s recommended to put the lawn clippings in bags to prevent the weeds from reseeding and invading the lawn.
  • When the grass is too long. Grasscycling doesn’t contribute to the formation of stubble when good mowing practices are adopted and the soil enjoys biological health. However, if the grass is allowed to grow too long before it’s cut, the large amount of clippings generated by mowing can lead to an accumulation of stubble.
  • When the cut grass is wet. In this case, clippings risk not being distributed uniformly over the lawn and may suffocate it if they form layers more than 0.5 centimeters thick.

Other good mowing practices

The lawn will look better, be more disease-resistant and regrow more easily if you regularly sharpen your lawnmower blades, because a clean cut allows for better healing. As a general rule, a dull lawnmower will cause a lawn to turn greyish-green, the color change caused by grass tips dying and turning brown.

Avoid mowing your lawn when it’s wet – it will cut more cleanly and the clippings will be better distributed over the entire lawn when it’s dry.

Don’t mow the lawn in very hot and dry weather.

Finally, mow in a different pattern each week so that the clippings don’t form clumps.

Add this