Ask any professional landscaper what single service homeowners most underutilize and the answer is almost always the same: aeration. It's unsexy, it doesn't look impressive while it's being done, and the results are gradual — which means most people skip it. That's a mistake.
What aeration actually does
Soil compaction is the root cause of a surprising number of lawn problems in the GTA. Our clay-heavy soils compact easily under foot traffic, freeze-thaw cycles, and the weight of snow and water. Compacted soil has tiny air pockets squeezed out — which means roots can't grow deep, water runs off instead of soaking in, and fertilizer sits on the surface instead of reaching the root zone.
Core aeration removes thousands of small plugs of soil from your lawn (typically ½ to ¾ inch diameter, 2–3 inches deep). This creates channels for air, water, and nutrients to reach the root zone — and gives roots room to grow deeper.
Signs your lawn needs aeration
- It dries out quickly even when you water regularly
- Water puddles or runs off instead of soaking in
- Heavy foot traffic areas are thin or bare
- The soil feels hard and you can barely push a screwdriver more than 2 inches in
- Thatch buildup (often goes hand-in-hand with compaction)
Core aeration vs. spike aeration
Core aeration (which removes plugs) is dramatically more effective than spike aeration (which pokes holes without removing anything). Spike aeration can actually increase compaction by pushing soil sideways rather than removing it. Always specify core aeration when booking.
When to aerate in Ontario
Best window: Early fall (late August – mid-October). Soil is warm, grass grows aggressively into the aeration holes, and fall rains help. This is the preferred window for most Ontario turf.
Second option: Spring (late April – May). Works well, but weed seeds also germinate more readily in spring. If you aerate in spring, be prepared to manage more weed pressure.
Never aerate during summer heat stress or when the lawn is dormant (frozen ground in winter). You're trying to help the grass recover — timing it when the grass is already stressed is counterproductive.
What to expect after aeration
Your lawn will look strange for a week or two. The soil plugs left on the surface are normal — they break down within 2–3 weeks and return organic matter to the soil. Don't rake them up.
Over the following 4–6 weeks, you'll notice grass filling in the holes, often thicker than before. If you overseed immediately after aerating (highly recommended), seed germination rates are dramatically higher because seed falls directly into the holes and has perfect soil contact.
How often should you aerate?
For high-traffic areas or clay-heavy soil (common in much of the GTA), annually. For average lawns, every 2–3 years is sufficient. If your lawn looks consistently healthy and water soaks in well, you may not need it at all — but most Ontario homeowners benefit from at least every-other-year aeration.