How Short to Cut Grass for the Last Mow of the Season

For the last mow of the season, cut your grass to about 6 cm (2.5 inches). University extension experts put the final cut between 5 and 7.5 cm (2 to 3 inches) for the cool-season grass most Canadian lawns grow. Don't go below 5 cm (2 inches). Get there in small steps, and never take off more than one third of the blade in one cut.

What height should the last mow be?

Here's what the official sources say. They don't all pick the exact same number, but they land close together.

• University of Nebraska-Lincoln: set the mower lower for the last mow, to 5 to 6.5 cm (2 to 2.5 inches). They say it helps the lawn get ready for winter and fights snow mould.
• Iowa State University Extension: drop to 6 to 7.5 cm (2.5 to 3 inches) from mid to late September, and keep it there.
• City of Greater Sudbury: cut grass to 6 to 8 cm (2.5 to 3 inches) all season.
• University of Saskatchewan: mow at your normal height in autumn, and don't cut lower than your grass type likes.

Put those side by side and 6 cm (2.5 inches) fits all of them. It's short enough to stand up under snow. It's tall enough that you're not scalping the lawn. That's the number we'd pick for most yards from BC to New Brunswick.

If your lawn has some shade or thin spots, lean toward 6.5 to 7.5 cm (2.5 to 3 inches). Don't push past the bottom of the range just to make the lawn look tidy.

Why cut shorter for the last mow?

The big reason is snow mould. The University of Saskatchewan says snow mould comes from fungi that like the cold and the wet. It shows up in spring, after the snow melts.

USask lists what sets it up. Two of the main ones are lawn care jobs you can do this fall:

• Grass left long, so it flops over and mats down under the snow.
• Leaves left lying on the lawn all winter.

Their advice is short: cut and rake the lawn before snow arrives. Long blades fold over into a damp mat. A shorter lawn stays more upright and dries faster in spring. For the full picture, read our guide to snow mould and fall cleanup.

Can you cut grass too short before winter?

Yes, and it's a common mistake. Some people "scalp" the lawn on the last cut, thinking short means less work in spring. It doesn't.

The University of Saskatchewan says grass mowed too low lives in constant stress. It gets more disease, and weed seeds move in more easily. If the short mowing keeps up, the grass can die.

Nebraska notes that a taller fall cut protects the crown and helps roots grow. That's why the experts lower the deck a little for the final cut, not a lot.

So keep the 5 cm (2 inch) floor in mind. On bumpy yards, the mower can dip and scalp the high spots even at a safe setting. Raise the deck one notch on rough ground.

How do you step down to the last-mow height?

Use the one-third rule. Iowa State says never take off more than one third of the leaf in one mow. USask puts it at 30%. Sudbury says the same, warning that a bigger cut can shock the plant.

Here's what that means with real numbers:

Grass height before the cut	Lowest safe cut
9 cm (3.5 in)	6 cm (2.5 in)
7.5 cm (3 in)	5 cm (2 in)

If your grass is 9 cm (3.5 inches) tall, you can go straight to 6 cm in one cut. If it's taller than that, go down one notch per mow over a couple of weeks.

A few tips that make this easier:

• Measure, don't trust the dial. Mower deck numbers don't always match the real cut. Use a ruler on a mowed patch.
• Mow before it gets too tall. If growth spurts in a warm, wet week, cut sooner rather than later.
• Use a sharp blade. Sudbury says to sharpen mower blades every year. A dull blade tears the tips, and a short cut shows every ragged edge.

When should the last mow happen?

Don't pick a date off the calendar. Watch the grass. Iowa State says to keep mowing until the grass stops growing. Cool-season grass like Kentucky bluegrass stops when daytime highs stay below 10°C (50°F). After that, the mower can go away for the winter.

So your last mow is the first cut after the lawn has stopped growing for good. In practice:

• Daytime highs have stayed under 10°C (50°F) for a while.
• The lawn looks the same a week after your last cut.
• The leaves are mostly down, so you won't need to mulch or rake again.

That timing shifts a lot across Canada. Prairie and northern lawns wind down sooner than lawns in Windsor or Hamilton. Our guide on when grass stops growing has the normal fall highs for cities across the country.

One more thing: don't mow frosted grass. The frozen blades snap, and your footprints can leave brown tracks. Wait until the frost melts and the lawn dries.

What about the leaves on the last mow?

Deal with them on the same day. Iowa State says a layer of leaves that hides the grass needs to be managed. You can rake it off, or chop it up with a mulching mower so it breaks down into the soil.

The last mow is a good time to do both jobs at once. A pass with the mower chops light leaf cover. Heavy piles need raking or bagging. Then the lawn goes into winter short and clear, which is just what USask suggests for snow mould. See our tips on mulching leaves with a lawn mower for how much a mower can handle.

What else goes with the last mow?

The final cut is usually part of a bigger fall tidy. Here's what to tick off that day:

• Walk the yard first and pick up sticks, toys and hoses.
• Trim along fences, walks and beds so the edges match the lawn.
• Clear leaves out of beds and corners where they pile up.
• Sweep clippings off the driveway and sidewalk.
• Clean the mower deck before you store it, so wet grass doesn't sit in it all winter.

Our fall lawn cleanup checklist covers the rest of the season's jobs.

Can someone else handle the last mow?

Yes. Golden Oak Lawn Care matches you with a vetted, insured local crew in your city. They do the work. We stand behind it with the Golden Oak Guarantee.

Your crew can do the last cut as part of a fall cleanup: final mow at the right height, edges trimmed, leaves raked and bagged or hauled away. If you'd rather not think about it all year, the Worry-Free Lawn Season covers regular lawn mowing from spring to fall. The same crew comes every visit and texts you a photo when the job is done.

We price every lawn by its size from satellite images, so no one needs to visit. Lawn size, how often you want cuts, slopes, gates and leaf volume all change the price.

Want it handled? Get your price in 60 minutes, or call 1-866-904-LAWN.

Last Mow Questions

Sources: University of Nebraska-Lincoln fall turf tips, Iowa State late summer and fall lawn care, Iowa State: when to stop mowing, USask managing your lawn, USask snow mould, City of Greater Sudbury lawn care.