How to Mow Your Lawn in Hot Weather and Keep It Green

When the dog days of summer bring on their swelter, it's time to rethink how you mow your lawn. Though a low-cut, manicured lawn might seem ideal, turf grass actually does better in the summer heat when you let it grow a bit. Longer shoots mean deeper roots, which the lawn needs to suck up moisture from the soil. A shaggy lawn also shades the soil, minimizing evaporation. To achieve that look, you'll need to raise the height of your lawn mower's deck—that is, the machine's main body, which houses the blade. Lawn mowers today, including the top-scoring models in our lawn mower ratings, have height adjustment levers that make it easy to raise and lower the deck. You'll actually need to use a ruler to determine the precise setting, at least until you get familiar with your machine. What Matters to You Matters to Us We test thousands of products so you can create your best home. Join After the spring growing season, CR recommends letting grass grow to about 4½ inches before mowing it to 3 to 3½ inches. When the heat starts to ease off later in the season, you can drop back down to 2½, for a more manicured look. Here’s how to adjust the deck and clean it to keep your mower in peak condition. Step 1: Measure Current Cutting Height Roll the mower onto a level surface, like the driveway or garage floor. If it's a battery-powered mower, ensure it doesn't start up while you're working by removing the safety key. To take the same precaution with a gas mower, detach the spark plug wire from the spark plug; it's typically located on the front of the mower. "The wire is insulated by a rubber casing and takes some wiggling to get off," says John Galeotafiore, head of Consumer Reports' home improvement testing. "But it's not that hard to do, and the wire and its casing reattach easily to the spark plug." Lift up the side or rear-discharge flap covering the opening that expels cut grass. You'll see the blade inside. Determine the current blade height by measuring the distance between its bottom edge and the ground. It’s worth noting that most manufacturers ship mowers from the factory with their decks in the lowest position—often as low as 1½ inches, which can scalp a lawn even during ideal weather conditions. Step 2: Adjust the Deck Height Lawn mowers come with notched adjustment levers that raise and lower the wheels, thus changing the distance between the deck and the ground. For walk-behind mowers, there may be one lever for each wheel, one lever for the rear wheels and another for the front wheels, or a single lever for all four wheels. With riding mowers, one lever moves the deck up and down, independent of the wheels. We find that all configurations are easy to operate once you get the hang of it. But the notches don’t always provide a corresponding cutting height, so it couldn't hurt to take a measurement with your ruler after making the adjustment to ensure you’re at the correct cutting height. Step 3: Clean the Deck