How Often Should You Cut Your Lawn in Ontario?

If you live anywhere in the GTA — Burlington, Oakville, Mississauga, Vaughan, Markham — the honest answer is: more often than most homeowners think in May and June, and less often than most homeowners think in August. Mowing schedule is one of the biggest levers you have on lawn health, and Ontario's compressed growing season makes the timing matter even more than it does further south.

The one-third rule

The single most useful rule in lawn care: never remove more than one-third of the leaf blade in a single cut. Cool-season grasses common across Ontario (Kentucky bluegrass, fescue, perennial ryegrass) photosynthesise in the upper portion of the blade, so a hard scalp stresses the plant, exposes soil to weed seeds and invites disease in our humid summers.

If your target mowing height is 3 inches, you cut when the lawn is 4.5 inches — not when it's a jungle at 7.

Month-by-month mowing schedule for the GTA

April — wait for growth

Resist the urge to start mowing on the first warm Saturday. Cutting cold, dormant grass damages crowns. Wait until you see consistent green growth and the lawn is over 3 inches — usually mid-to-late April in most GTA neighbourhoods.

May — peak growth, weekly cuts

May is the heaviest growth month of the year. Mow every 5–7 days at 3 to 3.5 inches. Keep blades sharp — a torn leaf tip turns brown and makes the whole lawn look hazy from across the yard.

June — weekly, then 7–10 days

Early June stays on a weekly schedule. As temperatures climb into the high 20s, growth slows and you can stretch to 7–10 days. Raise the deck to 3.5 inches: taller grass shades the soil, holds moisture and outcompetes crabgrass.

July & August — 10–14 days, raise the deck

Cool-season lawns slow dramatically in mid-summer heat. Cut every 10–14 days at 3.5 to 4 inches. If we hit a dry stretch and you're not irrigating, stop mowing entirely — cutting drought-stressed grass causes more damage than a long lawn does.

September — back to weekly

September is the second peak growth window. Drop back to weekly mowing at 3 to 3.5 inches. This is also the best month of the year for overseeding any thin patches.

October — final cuts, lower height

Through October, gradually drop the height to about 2.5 inches over the last two or three cuts. A slightly shorter final cut helps reduce snow mould risk over the winter.

Signs you're cutting too often or not often enough

• Brown leaf tips a day after mowing → blades are dull or you cut too much off at once.
• Heavy clippings choking the lawn → you waited too long; bag the next cut, then resume mulching.
• Thinning, yellowing patches in July → you're cutting too short in the heat.
• Crabgrass invading from the edges → height is too low and soil is exposed to sunlight.

When to call a pro

If a weekly mow eats your Saturday morning or you're juggling cottage weekends, a recurring lawn cutting contract is one of the highest-leverage services you can buy. We mow on a tight schedule across the GTA, alternate cut direction each visit (which prevents ruts and grain) and bag or mulch based on what your lawn needs that week.

Pair lawn cutting with a spring and fall clean-up and you've covered 90% of what a healthy GTA lawn needs all year.