Just last month, Minnesotans found themselves stuck in the middle of a heat wave—with some areas reaching 100° F. Though extreme temperatures are nothing new to those of us living in the Midwest region, it doesn’t make the experience any less stressful.
And that type of stress doesn’t just end with trying to keep our homes cool or our families and pets hydrated. Heat stress can also impact your landscape.
Like you, your grass, shrubs, trees, and plants are all living species. Which means when the heat goes up and the moisture goes down, they become thirsty, too. Also like you, they require a bit of TLC to make it through the dryer spells of the year.
Therefore, in addition to taking extra precautions for you and your family’s health needs during the hotter times of year, be sure you’re paying careful attention to your lawn’s needs, too.
Lawn Care During the Summer
As experts in organic lawn care, we often get asked for tips and best practices on how to maintain a healthy lawn during the dog days of summer. And one question on everyone’s mind is this: should I mow when it’s hot?
Before we can answer this common question, let’s first define what we mean by “hot” temperatures, or more specifically…what temperature is “too hot” to mow grass.
When temperatures go beyond 80°F, your cool-season grass may begin to struggle. And when high temperatures last for extended periods of time, it can cause your grass’ growth to slow down and its vibrant green color to fade. In fact, some cool-season grasses will go dormant during the hot summer months until early fall.
During a heat wave—a period of abnormally hot weather that lasts longer than 2 days—it’s recommended that you do not mow your lawn.
When is it too hot to mow your lawn
You may think that noon is the hottest part of the day, since the sun is at its highest point in the sky. But according to the Almanac, 3 p.m. is actually hotter, as the sun is lower in the sky, allowing its outgoing heat to be much greater.
You may also think that mowing your lawn in the early morning, when the temperature is cooler, is the best time to mow during the summer. However, that time of day should be reserved for watering your grass, especially during a heat wave or when your grass is heat stressed.
So, what’s the best time of day to mow a lawn in hot weather?
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.
How to Mow Your Lawn During the Summer
Do you love the look of freshly cut green grass—with those perfectly parallel strips laying across the front of your yard? Most of us do. But it might surprise you to learn that when we enter those long, dry summer days, it’s best to keep your grass high and to change your mowing patterns. Mowing in different directions can help your grass grow straight up and stand tall vs. leaning one way.
Therefore, you’ll need to raise your mower’s blades, so you can allow your grass to stand tall and grow a deeper root system into the soil. This way it can access water and other nutrients. If you’re caring for cool-season grass, mow at a high setting, so your grass is at least 3″-4″ tall.
Also, be sure your blades are kept clean and sharp to prevent tearing of your grass, which is common during high temperatures.
How often you decide (or need) to mow your lawn will depend on many factors. For example, mowing every 4-6 days may be sufficient, but if your grass is experiencing heat stress or has become dormant, you won’t need to. The most important thing is to avoid cutting more than ⅓ of the blade off at a time. This is especially important in the heat of the summer.
Want more tips and ideas on how to keep your lawn vibrant and healthy all summer long? Contact our team today to learn about our services. Be sure to stay connected to our blog for more lawn care articles and resources.
FAQs
In fact, some cool-season grasses will go dormant during the hot summer months until early fall. During a heat wave—a period of abnormally hot weather that lasts longer than 2 days—it's recommended that you do not mow your lawn.
What temperature is too hot to mow grass? ›
'As a general guideline, you want to avoid mowing your lawn in temperatures above 90°F,' says Ryan Farley, CEO of Lawn Starter. 'When it's excessively hot, the grass is already under stress due to heat and potential dehydration. Mowing can exacerbate this stress and potentially damage your lawn.
When should you not mow? ›
Never mow grass which is wet or frosty, as this can compact the soil and harm your turf. Wait until after the lawn has dried to perform mowing.
Can you mow the lawn in the heat of the day? ›
If temperatures are forecast to be extremely high for an extended period, it's best to avoid mowing your lawn until the hot spell passes. According to research from the University of Melbourne, mowing the lawn during a heatwave can cause significant damage to grass and make it more susceptible to disease.
How do you cut grass in extreme heat? ›
TIP: For mowing in the heat of summer, follow the one-third rule but let your grass grow roughly . 5 of an inch higher than the recommended cutting height. Never remove more than one-third of your grass height at one time because this will lead to more stress, potential scalping of the lawn and/or disease.
Is it OK to mow when its 90 degrees? ›
Mowing a lawn in the middle of a summer heatwave is one of the worst things you can do to it. When temperatures reach around 85 degrees, grass, like many other green plants, begins to suffer – especially cool-season grasses such as Kentucky bluegrass, perennial ryegrass, and fine fescues.
Is it better to leave your grass long in hot weather? ›
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.
Why aren't you supposed to mow in May? ›
The history. No Mow May was first popularized by Plantlife, an organization based in the United Kingdom, but is now gaining traction across North America. The goal of No Mow May is to pause mowing during the month of May, allowing flowers to bloom in your lawn to help early season pollinators.
What temperature does grass stop growing in summer? ›
Grass generally stops growing once temperatures drop to below the range of 50-55 degrees Fahrenheit or reach above 90 degrees Fahrenheit. Since soil takes longer than air to lose and retain heat, it will take a period of a least a few days for a temperature change to impact the growth of grass.
Why shouldn't you mow your lawn every week? ›
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.
In general, lawns in summer need about ½” of water every 3 days or so. If it's a little cooler where you are, say, in the high 70s, then you could get away with ½” every 3-4 days. If it's hotter where you are, say, 85 and sun all day, then maybe every 2-3 days.
Can I water my lawn after mowing? ›
Watering after mowing can aid in the grass blades' recovery, promoting faster and healthier regrowth but as mentioned above, be careful not to overwater. Watering in the early morning minimizes water loss through evaporation, allowing moisture to penetrate the soil and reach the roots.
How often should you mow your lawn in summer? ›
One of the most common questions we hear is, “How often should you mow your lawn in the summer?” Over the summer you'll generally mow your lawn every 4 to 6 days. If there is a lot of rain or if you fertilize heavily, you'll want to mow every 4 days to keep your grass from getting too long.
At what temperature should you not cut grass? ›
If you must mow your lawn after a frost, the best practices are to ensure that your lawn does not have a lot of moisture from snow or ice and make sure to not mow the lawn when the temperatures are below 40 degrees Fahrenheit.
When not to cut grass? ›
Never mow wet or frosty grass
This can damage your turf and compact the soil. Wait until later in the day when the lawn has dried out or defrosted, or postpone mowing to another day.
Why is my grass dying in the heat? ›
Often this is due to improper watering to keep your lawn healthy. Other signs and symptoms of heat stress include the following: Compacted lawns make it hard for moisture to reach the root and would greatly benefit from aeration. To check your lawn, you can take a knife or screwdriver and stab it into the lawn.
Is it safe to mow in 100 degree weather? ›
During a heat wave—a period of abnormally hot weather that lasts longer than 2 days—it's recommended that you do not mow your lawn.
What temperature is too hot for grass to grow? ›
Once temperatures reach 77 degrees, it becomes too hot for root growth, and root growth ceases. When temperatures reach 90 degrees, it becomes too hot for shoot growth and the grasses stop growing and begin to fall dormant, with the surface grass turning a brown hue.
Should you mow heat stressed lawn? ›
Once grass starts turning brown or wilting, or growth is slowing, it's important to hold off on mowing, nutrient, and pesticide application. Most homeowners can tell just by looking at their lawn if it is suffering, whether from heat stress or otherwise.
Is 90 degrees too hot to plant grass? ›
Grass seed needs a warm temperature to germinate and grow. The ideal temperature range for grass seed is between 55-85°F (12-29°C). Anything below 55°F (13°C) will inhibit the growth of your grass seeds, so it's important to keep an eye on the weather forecast when planting.
