When to Start Mowing in Sault Ste. Marie: Reading the Soo's Late Spring

In Sault Ste. Marie, start mowing once the grass is green, growing and about 10 cm (4 inches) tall. The ground should be firm enough to walk on without sinking. In an average year, that's sometime in May. April at the airport still brings about 20 frosty nights and 17 cm of snow. For the first cut, set the mower to 6.5 to 7.5 cm (2.5 to 3 inches) and take off no more than a third.

Why does spring come so late to Sault lawns?

The Soo sits at the east end of Lake Superior. The City's Official Plan says lake-effect snow gives it about 300 cm a year. The Plan calls that higher than average for this latitude.

All that snow has to melt before grass can do anything. Then the soil has to warm up. The Guelph Turfgrass Institute says cool-season grass starts growing once soil reaches 4.5 to 7°C (40 to 45°F). Soil warms slower than the air above it.

So a sunny April afternoon can fool you. The air feels like spring. The ground under the lawn is still cold and wet.

What do the numbers say about April and May?

These are Environment Canada climate normals for the Sault Ste. Marie airport, 1981 to 2010.

At the airport	April	May
Normal daily high	9.0°C	16.4°C
Days with a high over 10°C	about 12	about 26
Nights at or below 0°C	about 20	about 7
Normal snowfall	17.4 cm	0.6 cm
Snow on the ground at month end	0 cm	0 cm

At the end of March there's still about 8 cm of snow on the ground. By the end of April it's gone. But April is still mostly cold nights. May is when warm days take over. That's why most Sault lawns are ready for the first cut in May, not April.

How does the Soo compare to southern Ontario?

Frost dates tell the story. The average last spring frost at the Sault airport is May 29. In Hamilton it's April 29. In Windsor it's April 17.

That's a month behind Hamilton and about six weeks behind Windsor. So don't copy what your cousin in the south is doing. If they're mowing in April, that doesn't mean you should be.

A frost date isn't a mow date, though. Grass grows fine through a few cold nights. You just have to time the cut. Our post on the first mow of spring covers the signs that work anywhere in Canada.

How do you know your Sault lawn is ready for the first cut?

Skip the calendar. Walk outside and check these five things. When all five are true, it's time.

• The grass is green and growing, not flat and brown from the snow.
• Most of the lawn is about 10 to 11 cm (4 to 4.5 inches) tall.
• You can walk across it without leaving deep, wet footprints.
• The blades are dry. No dew, no rain, no frost.
• Leaves, sticks and winter junk are off the grass.

Tall grass on a soggy yard? Wait. Dry yard with short grass? Wait. You need both.

Why does the ground stay wet so long here?

The City's Official Plan notes that parts of the Sault have clay with a thin layer of topsoil. Clay holds water. After a big snow year, low spots can stay spongy well into spring.

UConn Extension warns that walking or working on wet soil packs it down. That compaction can hurt plants all season. A mower is heavy, and so are you. Give the yard a few more dry days if it squishes.

Can you mow if there's still frost at night?

Yes, if the grass is growing. A frosty morning in late May is normal in the Soo. The airport averages about 7 frosty nights in May.

The trick is timing. Mow in the afternoon, after the frost has melted and the blades have dried. NDSU Extension says dry grass clumps less and mulches into finer bits. Our post on mowing after a frost explains what goes wrong if you rush it.

How tall should the grass be before the first mow?

Use the one-third rule. NDSU Extension says to avoid cutting more than one third of the blade at a time. Cutting too much slows regrowth.

Their example: if you keep the lawn at 7.5 cm (3 inches), cut before it passes 11 cm (4.5 inches). Iowa State Extension suggests 6.5 to 7.5 cm (2.5 to 3 inches) for bluegrass lawns in spring.

Don't scalp it to "wake it up." NDSU says a short cut exposes more soil and leads to drought stress. Keep the deck up.

What if the lawn got away on you?

A wet May and a busy month can leave the grass shaggy fast. Take it down in steps. Cut a third, wait a few days, cut again a little lower.

Bag that first long cut or rake up the clumps. NDSU says clumps of long clippings can smother the lawn.

Don't let it run too long, either. Sault Ste. Marie's Yard Maintenance By-law 2012-10 says grass and weeds can't be over 20 cm (about 8 inches). The by-law gives owners at least seven days to fix it after notice. After that, the City can do the work and charge the owner. Details for your neighbourhood are on our Sault Ste. Marie lawn care page.

The boulevard counts too. The City reminds owners to cut the strip between the sidewalk and the curb next to their property. Where there's no sidewalk, it's the strip between the street and the property line. The same 20 cm limit applies.

What should you clear off the lawn before the first mow?

The snow hides a winter's worth of stuff. Clear it before the mower goes out.

• Pick up sticks, rocks, toys and anything the plow pushed onto the lawn.
• Rake off old leaves. UConn Extension says leaves left in spring slow green-up and delay growth.
• Check the mower blade. NDSU says dull blades tear grass tips and they turn brown.
• Clean up the edges along the walk and drive.

Where do the leaves and sticks go in the Sault?

The City picks up leaf and yard waste every two weeks and turns it into compost. Leaves, grass clippings and garden waste go in biodegradable paper bags only. Each bag can weigh up to 20 kg (44 pounds).

Branches don't go in the bags. Take them to the brush dump at the City Landfill, 402 Fifth Line East. Extra leaves can go to the Leaf and Yard Waste Bunker there.

Did you bag leaves last fall and miss the last pickup? The City lets you store them until spring collection starts again. Check the City's calendar for your week.

What about grey or pink fuzzy patches?

That's often snow mould. The University of Saskatchewan says it shows up after the melt and fades with warmer, drier weather. Lawns usually recover well. Rake the patches when the lawn is dry, and wear a mask if you're sensitive. Our partner crews don't spray, and we don't give spray advice.

How often should you mow after the first cut?

More often than you'd guess. Spring is when grass grows fastest. NDSU says you may need to mow every 5 days in spring.

In the Soo, spring starts late, so plan on frequent cuts right from the first one. Miss a week and you're back to a long, clumpy cut. Leave normal clippings on the lawn. NDSU says they shade the soil, hold moisture and recycle nutrients. Just sweep them off the drive.

Can someone else handle the first cut and the season?

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

Your crew can start with a spring cleanup to clear the leaves and sticks. Then they move into regular lawn mowing once the grass is growing. With the Worry-Free Lawn Season, the same crew comes every visit and texts you a photo after every cut. Your first cut is free when you book the season.

We price every lawn by its size from satellite images. Lawn size, how often you want it cut, slopes, gates and obstacles all change the price.

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

Sault Ste. Marie First Mow Questions

Rules change, so check with the City before you plan. Sources: Environment Canada climate normals, Sault Ste. Marie A, City Official Plan, City by-law enforcement, By-law 2012-10, City boulevard notice, City leaf and yard waste, City leaf collection notice, Guelph Turfgrass Institute, NDSU Extension mowing, Iowa State mowing height, UConn soil compaction, UConn leaf management, USask snow mould.