How High to Mow a Lawn in Nunavut

Mow Kentucky bluegrass and fine fescues at 2 to 3 inches, tall fescue at 3 to 3.5 inches, and perennial ryegrass and rough bluegrass at 1.5 to 2.5 inches. Only cool-season grasses have a chance this far north. The ranges are far enough apart that mowing one species at another’s height can cost you the lawn. Nunavut lawns are rare, and the grass gets only about twelve weeks between the average frost dates to build itself up.

The mowing height for Nunavut lawns

A blade of grass works like a small solar panel. The more leaf you leave standing, the more sunlight the plant turns into sugar, and the more of that sugar goes into roots. Taller grass also shades the soil, which keeps it cooler and makes it harder for weed seeds to germinate. Where the growing season is this short, every inch of leaf counts, and that is why a Nunavut lawn should sit in the upper half of its species range rather than the lower.

Here are the heights for the five cool-season species that suit this territory:

If you are not sure what is in your seed mix, 2.5 inches is a safe middle. It falls inside the ranges of four of the five species. Only tall fescue wants more. Mowing tall fescue at 2 inches, or ryegrass at 3.5, is where lawns get thin.

Why warm-season grasses are left out

Warm-season grasses do their growing in sustained heat and go dormant when it cools. Rankin Inlet’s average last spring frost is June 19 and its average first fall frost is September 13. That leaves about 86 days between them, and a warm-season grass would barely wake up before the next frost shut it down. Cool-season species start growing in cool soil and keep going in mild weather, so they use the whole short window.

These heights come from extension sources in the United States (Clemson, NC State, University of Illinois, Purdue and others), and each figure sits inside the range those sources give. A mowing table written specifically for Nunavut is not published here. For territory-level questions, start with Agriculture and Agri-Food Canada. For the general method, see Mowing a Lawn. A neighboring territory with its own numbers is covered in How High to Mow a Lawn in Northwest Territories.

Raising the deck when the heat comes

On a warm, dry stretch in July, move the deck to the top of your species range. A tall fescue lawn goes to 3.5 inches, bluegrass and fine fescue to 3 inches, and ryegrass to 2.5. Longer blades shade the crown and the soil beneath them, so less moisture evaporates. They also keep roots from baking in the surface layer. A lawn that is scalped during a heat spell has the least leaf and the most exposed soil at the worst moment.

Rainfall does not let you off the hook. At Rankin Inlet A, the Environment and Climate Change Canada station, the 1981-2010 normals show 127 mm (5.0 inches) of rain across June, July and August, and 310 mm (12.2 inches) over the year. June is the driest summer month at 27 mm (1.05 inches). July brings 42 mm (1.65 inches) and August 57 mm (2.26 inches). Those are long-term averages for one station, not a forecast, and they cover 1981-2010, so they are not directly comparable to the 1991-2020 normals used for US states on this site.

What those millimeters do in your yard depends on the soil. A sandy surface lets rain through within the day, while clay can hold the same rain for a week. A sandy lawn can look parched after a month that was average on paper. Rain that comes in one hard burst mostly runs off instead of soaking in, so 27 mm in June may be one downpour or several gentle days, and the lawn will not care about the total. A slope, a building’s rain shadow or a gravel pad changes the picture again.

That is why a cheap rain gauge on your own plot settles the question better than any normal. If a week passes with under an inch in the gauge and the blades are turning gray-green or staying flattened after you walk across them, the lawn is asking for water. Cutting it shorter will not help.

The one-third rule, and why it is not arbitrary

Never remove more than one-third of the blade height in a single mowing. The reason is simple. Cut off half the leaf at once and you take away much of the plant’s ability to feed itself, so it pulls energy from the roots to regrow. Roots then stop growing for a while. A lawn that is cut that way repeatedly ends up with a shallow root system and little reserve, which matters even more where the season is short.

The rule turns into a schedule once you know your target height. Mow when the grass reaches 1.5 times the height you want to leave:

Grass at 5.25 inches is common after a missed week, and it is a trap. Taking tall fescue from 5.25 inches straight to 3.5 is a fair cut. Dropping it to 2 inches to make up for lost time is not. If the lawn got ahead of you, cut it back in two stages a few days apart, easing down to your target.

This rule also tells you how often to mow, which a calendar cannot. In a cool, slow stretch, the grass may take two weeks to gain the inch and a half it needs. After a stretch of rain it may need a cut in five days. Mow by height, not by the day of the week. When the growing window is only about twelve weeks long, a lawn that is cut on time spends more of it growing and less of it recovering.

The first and last cut of the year

The Rankin Inlet A average last spring frost is June 19, and the average first fall frost is September 13. Both are mean dates, which means the midpoint of a window. In one year out of two, the frost arrives later than the average date. Do not treat June 19 as a safe date, and do not treat September 13 as the day growth stops. The figures also come from one station, and districts farther north or at higher elevation can run weeks behind it.

For the first cut, let the grass tell you. Wait until it is actively growing and tall enough that you can take off the top third and still leave your target height. For a 3-inch lawn, that is 4.5 inches. A lawn that has just come out from under snow is fragile, so set the deck at the top of the range for the first cut. Tall fescue goes at 3.5 inches, bluegrass and fine fescue at 3.

The last cut matters just as much. Keep mowing at your usual height until growth stops, and do not drop the deck low “to get ahead of winter.” Grass left too long can mat down under snow and stay wet, which invites snow mold. A cut that is too short leaves the crowns exposed. Staying inside the normal range for your species avoids both problems. Read the lawn rather than the date. If frost arrives before September 13, your last cut may be early, and if it comes weeks later, you may have one more.

The rainfall and frost figures describe one station. A neighbor’s lawn in the same community can behave differently, depending on soil, slope and exposure. To compare with a milder case, see How High to Mow a Lawn in Delaware, where the same species face a much longer season.

Common questions

Can I mow below 1.5 inches to keep it neat?

No. None of the five species here has a recommended range that goes below 1.5 inches, and that is only for perennial ryegrass and rough bluegrass. Bluegrass and fescues want at least 2 inches, tall fescue at least 3. Shorter cuts weaken the lawn in a place where it has little time to recover.

What height works if I do not know my grass mix?

Use 2.5 inches. It sits inside the ranges for Kentucky bluegrass, fine fescues, rough bluegrass and perennial ryegrass. If the mix includes tall fescue, go up to 3 inches so that it stays at the bottom of its own range.

Do Rankin Inlet’s numbers apply across Nunavut?

No. The frost dates and rainfall come from a single station, Rankin Inlet A, and a territory is not one climate. Treat them as an example of what one region can expect. A rain gauge and your own notes on when frost arrives will serve you better than any published average.

How often should I mow?

Whenever the grass has grown to 1.5 times your target height, since that keeps each cut at one-third of the blade or less. In cool weather, that may be every two weeks. After a run of rain or warmth it can be sooner. Measure with a ruler once, and after that you will learn to judge it by eye.