However, most professional gardeners would agree that between 8 AM and 10 AM is the best time of day to cut your grass. The reason for that is that lawns need time to heal before evening. Grass needs the benefit of the day to dry and heal before dusk settles.
Mid-morning (between 8 and 10 a.m.) tends to be the best time of day for mowing your lawn. It allows enough time for dew to dry, resulting in strong, perky blades of grades, while avoiding the hottest periods of the day.
Plan to mow your lawn during the evening hours, after the heat of the day has passed. The temperature should be between 40°F and 80°F.
If the grass is too wet, you shouldn't mow and if it's too dry you shouldn't either. Remember, mowing is a stressful event for your lawn. If you mow when it's already under stress, such as during dry spell or drought, then it will become even more stressed. You don't like to be stressed and neither does your poor lawn.
Early Morning (6–8 AM)
The grass is probably still wet with dew, which means the mower will likely rip the grass, bruise it and it will subsequently take longer to heal. Your mower deck will clog faster, leave tracks, make clumps and cause the grass to mat.
To minimize disturbance and maximize efficiency, the best time to mow your lawn is in the morning, around 8am to 10am. This way, it's not too hot for physical exertion, and it's late enough that the morning dew has dried.
While it might be tempting to mow your lawn as soon as the rain clears, you're better off waiting until the grass is dry. Cutting wet grass can lead to plant fungal diseases, soil damage, and even mower operator injury—all of which are preventable with a little patience.
Cut your lawn to possibly the shortest height you have all season. The ideal height is around 2 1/2 inches. Cut it too low and the grass might not be long enough to photosynthesize and provide nutrients to the roots. Too high and the frost might become matted after a snowfall.
When grass is too dry. There's nothing wrong with mowing your turf in a drought, but there are some changes that need to be made to minimize the chance of damage. Raise your mower's deck height by a half of an inch when grass is drought stressed, as thirsty grass will grow at a slower rate.
Mowing every two weeks — instead of weekly — and not dousing grass with chemical herbicides and fertilizers, helps the environment and supports the health of bees, which are among the world's most important pollinators.
'As long as your blades are sharpened, and the grass isn't not soaking wet, mowing in the early morning dew is totally fine,' says Douglas Dedrick.
A mowing height between 2.5 to 3 inches is best for most of the season, except during summer stresses when the lawn mowing height should be raised one-half inch to mow at 3 to 3.5 inches. Raising the mowing height provides more insulation from summer heat and reduces water loss from your soil.
How often should you mow? Normally, weekly mowing is the rule, but some lawns need cutting more often. Other lawns will grow more slowly and might need cutting only once every ten days or two weeks. Generally, don't cut off more than one third of the grass blade.
For this reason, some people prefer to mow at 3 or 3.5 inches. For the healthiest and most sustainable approach, Michigan State University Extension says 3.5 to 4 inches is most desirable. Lawns mowed at 3.5 or 4 inches out-compete weeds, tolerate grubs and look just as good as lawns mowed at 2.5 inches.
Once grass starts to grow again, it's okay to mow with your mower set to 3 ½ inches. Do not scalp the lawn to try to remove brown blades of grass. Let new fresh grass grow around them. Leave grass clippings on the lawn to fertilize the lawn naturally.
AVOID MOWING DURING EXTREME HEAT When your lawn is particularly stressed from heat or drought, it can be limited in its ability to recover from mowing and can be damaged even more. Instead, mow the grass after a rainfall or after irrigation day.
Mow your cool season grass to 3 or 3.5 inches in summer, or up to 4 inches for tall fescue and perennial ryegrass. Warm season grasses should round out at about 2 to 2.5 inches.
Ideal grass length
The mowing height range for most grasses is between 1.5 and 3 inches. In general, for most lawns 2 to 2.5 inches is optimum because if you are mowing at 3 inches, your lawn may grow to 5 or 6 inches before you mow it again.
How to Mow Your Lawn to Prepare it for Winter. Once the grass growth slows down, continue to mow your lawn each week as you normally would. Each week you'll be able to lower your cutting height slightly, so that you're always removing 1/4 - 1/3 of the grass blade. Do this until the lawn is about 2 - 2.5 inches tall.
Is mowing before or after rain better? It is always better to mow before rain if possible. If your grass is dry, but you see rain on the way, it is a good idea to mow the yard before the rain arrives. Otherwise, the next best time to mow is when your grass has completely dried after rainfall.
The resulting uneven look would be bad enough, but when you try to cut damp grass—the result is a tear rather than a clean cut. These tears open the door for fungus and moisture provides a medium for fungus to spread, so when you mow a lawn that's wet, you're creating a perfect storm for fungal infestations.