The Best Time to Water Your Lawn (and Why It Matters for Mowing)

The best time to water your lawn is early morning, before the day heats up. Barrie, Lethbridge and Alberta Agriculture all say so. Less water is lost to sun and wind. The grass also dries out during the day, so it's dry by mowing time. Evening watering leaves grass wet all night, which can invite disease. Give it about 2.5 cm (1 inch) a week, rain included, in one or two deep soaks.

Why is early morning the best time to water?

Morning is cool and calm. The sun is low, so less water burns off before it soaks in. Alberta Agriculture's lawn tips say early morning watering is ideal because less water is lost to evaporation and wind.

Aquatera, the water utility in Grande Prairie, puts a number on it. It says the best time is 4 to 10 a.m., while the sun is low and it's still cool. Water at mid-day, it says, and you can lose 30% to evaporation.

That loss adds up. The Regional District of Nanaimo says up to 65% of the water used on lawns and gardens is wasted. It goes to runoff, evaporation or leaks. Its tip is the same: water early in the morning.

There's a second reason, and it matters for mowing. Morning water has all day to soak in and dry off the blades. By late afternoon, the lawn is dry and ready to cut.

Is it bad to water your lawn at night?

It's not a disaster, but it's not the best choice. Alberta Agriculture says evening watering leaves the lawn wetter longer. That raises the chance of disease problems.

The City of Lethbridge says the same thing in plain words. Evening watering can lead to fungal problems when the water isn't soaked up in the cool night air. Its advice is to aim for the morning hours.

Some cities do allow evenings. Hamilton has no set watering hours unless it tells you otherwise. It says early morning or late evening is best, because fewer people are using water then. Aquatera also lists evenings as an option.

So here's the simple rule. Morning first. If evening is the only time you can water, go early in the evening so the grass has a little time to dry. Midday in the heat is the worst choice of all.

A quick note on lawn disease: our partner crews don't spray, and we don't give fungicide advice. Good watering habits are the part you control.

How much water does a lawn need each week?

Most Canadian city guides land on the same number. Barrie and Kamloops both say a lawn needs about 2.5 cm (1 inch) a week. Barrie says that includes rain. Alberta Agriculture calls one inch an adequate soaking.

Lethbridge says summer lawns there need 2.5 to 5 cm (1 to 2 inches) a week.

How do you know when you've put down 2.5 cm? Use a tuna can. Kamloops says an empty tuna can is about 2.5 cm deep.

1. Set several empty tuna cans on the lawn at different distances from the sprinkler.
2. Turn the sprinkler on and start a timer.
3. Stop when the cans hold about 2.5 cm on average.
4. Write down the time. That's your weekly watering time for summer.

Got a rain gauge? Check it too. If it rained 1 cm this week, you only need to add about 1.5 cm.

How often should you water?

Deep and not too often. That's the advice from Nanaimo, Alberta Agriculture and Kamloops. Deep soaks push roots down into the soil. Short daily sprinkles keep roots near the top, where they dry out fast.

Kamloops says to water one to two days a week, depending on weather and soil. Sandy soil drains faster than silt or clay soil. So a sandy yard may need its water split into two soaks.

Too much water causes trouble too. Aquatera says over-watering can lead to shallow roots, weeds, fungus and disease.

Your city may also set your days and hours. Many cities set them. Our guides cover Kamloops watering rules, Kelowna watering rules and Nanaimo watering rules. Elsewhere, check your city's water page before you set a timer. The city's hours always come first.

Which parts of the yard need more water?

Not every patch of grass drinks the same. Alberta Agriculture points out a few spots that need different amounts.

• High spots and south-facing slopes: they dry out first, so they need more water.
• Grass under big trees: it needs more. Tree roots take the water, and the leaves catch rain before it lands.
• Shady spots: grass with less than 4 hours of direct sun a day needs less water.

This is why a few tuna cans help. You'll see right away if the sprinkler misses the far corner or soaks the shady side.

Why does watering time matter for mowing?

Wet grass and mowers don't mix. Hamilton says cutting wet grass can cause clumping. NDSU Extension says to mow when the grass is dry. That cuts down on clumps and chops the clippings finer.

Clumps aren't just messy. NDSU says they can smother the lawn underneath. Barrie's tips also say to cut your grass when it's dry.

So plan your watering around your mowing day. Here's what works:

• Water in the morning, mow later. Morning water dries by the afternoon.
• Skip the timer on mowing morning. If your crew comes early, water the day before instead.
• Don't water right after the cut in the evening. Wait for the next morning.
• Got clumps anyway? Hamilton says to mow the area again from a different direction to break them up.

Rain does the same thing as a sprinkler. Our FAQ on what happens if it rains on mowing day explains how crews handle it.

Does mowing height change how much you water?

Yes. Taller grass holds water better. Barrie says to leave your grass at least 6 cm long. The longer blades shade the roots and slow the loss of moisture from the soil.

Hamilton says to keep the mower blade at 6 to 7.5 cm (2.5 to 3 inches). Alberta Agriculture says to mow high, at 2.5 to 3 inches, and to take off no more than one third of the leaf at a time. It also says clippings don't clump when the mower is set higher.

Leave those clippings on the lawn. Barrie says they help the soil hold moisture. Our post on leaving grass clippings shows how to do it without a mess.

Our lawn mowing service page covers the height your crew cuts at. Our FAQ on how often to mow in Canada covers the schedule.

Is a brown lawn in summer dead?

Usually not. Alberta Agriculture says a lawn may turn brown in hot, dry spells. It's dormant, not dead. It greens up again when cooler, wetter weather comes back. A healthy lawn can stay dormant for several weeks.

So in a dry spell, you have two fair choices. Water deeply once or twice a week, within your city's rules. Or let it go golden and wait for rain. Don't flip back and forth with light sprinkles. That's the habit that wastes water.

How should you water your lawn in fall?

Water less as it cools off. Kamloops says to cut your summer watering time by up to half in spring and fall. Lethbridge says fall lawns there need about 5 cm (2 inches) every few weeks, not every week.

Lethbridge adds two more fall rules. If it rains or snows, don't add more on top. If the daytime high is below freezing, don't water at all. And keep watering in the morning.

Fall is also leaf season. Leaves left on the lawn can mat down over the grass. A fall cleanup clears them off and gives the lawn a tidy last cut before winter.

Who can handle the mowing while you handle the water?

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

With the Worry-Free Lawn Season, the same crew comes every visit. Your crew texts you a photo after every cut. If they miss your scheduled window, that cut is free. Watering stays with you, so tell your crew which days your sprinkler runs. They can plan around a wet lawn.

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

Lawn Watering Questions

Watering rules change, so check with your city before you set a timer. Sources: City of Barrie water conservation, Aquatera water conservation, Regional District of Nanaimo outdoor water use, Alberta Agriculture lawn care tips, City of Lethbridge Water Wednesday, City of Hamilton watering restrictions, City of Hamilton yard waste and mowing tips, City of Kamloops healthy lawns, NDSU Extension, how to mow your lawn.