Lawn aeration and topdressing: why, when and how?

Lawn is an important part of our landscaping. To have a beautiful, dense green lawn that is resistant to insects, weeds and weather, you need to take good care of it. Of course, you have to take care of the plant by providing it with the nutrients it needs to grow properly, mow it properly and water it as needed, but you must not neglect the soil in which it grows. Healthy plants start with good soil. In addition to feeding the grass, the soil must be nourished and its structure improved so that it can give back to the plants. Here are two simple and effective ways to improve your lawn’s soil.


Aeration is the mechanical tilling of the soil, by cutting holes in the lawn and removing pieces of soil, commonly called ‘’cores’’ to loosen and decompact the soil. The easiest way to aerate is to rent specialized equipment from a tool rental center and go through your lawn. Two passes are preferred to optimize aeration: lengthwise and widthwise, then up and down. Aeration allows water, air and nutrients to better penetrate and circulate the soil, which promotes deep rooting of the lawn.

Lawn aeration is done in the spring or fall. To find out if your soil needs to be aerated, do the pencil test: push a pencil into the soil. If you have trouble getting it in, your soil is too compact and needs to be aerated. Clay soils often need more aeration than sandier soils. If your soil is very compact, there is nor harm in aerating every year, or even twice a year.

Leave the soil cores in place, they will be quickly degraded by living soil organisms and rain. To speed up the job, you can break them up with your rake. To maximize the impact of your aeration, do a topdressing right after.


Topdressing is used to add organic matter to the soil in order to stimulate microbial activity and improve its structure. Many residential lawns have been established on poor quality soil. Topdressing can be used to improve the soil so that plants grow better. Using specialized equipment or a shovel, a thin layer of good quality topsoil or compost is spread over the entire lawn area. If the soil is very clayey, a portion of sand can help correct the soil structure. To know your soil type, have it analyzed at our garden centre.

Topdressing can follow the aeration of the lawn, but aeration is not essential for topdressing. In fact, if your soil is loose and well-drained, aeration is not necessary. You can topdress your lawn in the spring or fall. If you want to densify your lawn at the same time, add grass seed to your topsoil. A thick, dense lawn on good quality soil makes it much more vigorous and resistant to pest attacks. Keep the lawn moist by watering as needed for two weeks if you’re seeding at the same time as you’re topdressing.

Not sure how much soil you need for your lawn area? Use our calculator.

To find everything you need to take good care of your lawn all year as well as valuable advice, come visit us!

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