Most of us love long hot summers, where we can get our vitamin D fix, and enjoy barbecue and pool season to the max.
I wish I could say the same for our lawns.
Blazing sun, coupled with little or no rainfall can create all kinds of problems for the grass in our yards.
Thankfully, there are ways to treat lawn heat stress, and this article will give you the know-how for helping your turf through this challenging time.
- Heat Stress on Lawns – Too Long, Didn’t Read
- What is Lawn Heat Stress?
- How to Recognize Heat Stress in Your Lawn
- What to do About Heat Stress in Your Lawn
- How to Prevent Heat Stress in the Future
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Heat Stress on Lawns – Too Long, Didn’t Read
If you’re in a hurry, here’s a brief summary of what we’re going to explore:
- The signs and symptoms of lawn stress.
- How to treat it (which is basically to maintain an adequate and responsible watering schedule).
- Other lawn stress factors and their treatments during hot seasons.
I highly recommend you keep reading for some pro-tips and tricks on keeping your lawn as happy as you are through the summer.
But first, let’s find out what lawn heat stress actually is.
What is Lawn Heat Stress?
You may think your grass is dying from heat.
But actually, heat stress is dehydration in your lawn.
It’s a form of stress that your lawn experiences when it is exposed to heat with inadequate water for a prolonged period of time.
Interestingly, it’s not so much the temperature that causes lawn heat stress, but the length of time that the grass is forced to go without water.
Both cool and warm-season grasses can experience heat stress, but it’s much more common in cool-season grasses that aren’t adapted to drought conditions.
Warm-season grasses will last a lot longer than cool-season grasses without water before becoming stressed.
Usually, heat stress is what your lawn will experience just before it starts to go dormant, as dormancy is a protective mechanism against damage from heat stress.
How to Recognize Heat Stress in Your Lawn
There are a few different things that you can look for when trying to identify heat stress in your lawn.
- The overall lawn may appear to have shrunk due to a lack of water. It might look like the edges are pulling away from solid structures like paths or driveways, and cracks may appear through the lawn.
- The lawn will start to experience some discoloration, usually a slightly darker green, then yellowing, then browning. Discoloration can start at the tips and then slowly the whole blade of grass will turn a yellow or pale brown/tan color.
- The lawn might gradually change color as a whole, or change in patches.
- If you walk across the lawn and the grass doesn’t spring back into position but stays compacted, this is another sure sign of heat stressed grass.
- Compacted soil might also be an indication of heat stress. Using a pen or a screwdriver, drive the end into your lawn. If you meet with any kind of resistance – your lawn could be stressed, and you need to aerate. Keep reading for more information on this process.
What to do About Heat Stress in Your Lawn
The primary solution to heat stress is water.
Water rehydrates your lawn while helping to cool soil temperatures, which in turn slows down further moisture evaporation from the surface.
However, heat-stressed lawns are often so dry that they actually repel water rather than absorb it. This means the best way to water your lawn is by doing it in stages.
Start with a light watering on one part of your lawn, wait for it to soak in, and then move to the next patch. Once this light watering has been successfully absorbed, you can do a second round and aim for around half an inch of total watering.
It does sound time-consuming, I’ll admit. But don’t worry, your patience will pay off and this careful watering will definitely prevent your lawn from suffering further heat stress.
Ok, so it’s been a week, and you’re seeing some signs of green. That’s great!
But unfortunately, this isn’t a case of one-and-done. Your lawn will need consistent, regular watering throughout the remaining dry months to keep it happy.
To maintain the health of your lawn, aim for one or two deep watering periods per week.
Any more than this isn’t necessary. Less frequent, deeper watering is actually better for lawn health as it encourages deeper root growth which makes the grass more resilient.
Also, be sure to water early in the morning or late in the afternoon to avoid encouraging disease and unnecessary water loss through evaporation.
Watering your lawn can sound like a bit of science, right? There are definitely right and wrong ways to do it. But don’t worry, I have all the facts right here in this article to make it easy for you.
Summer Water Restrictions
Hot summers can bring about hosepipe bans and water restrictions – depending on where you live.
If your region is experiencing water shortages and its use is limited, then you may not be in a position to water your lawn at all.
In this case, you will have no option but to let nature take its course, and allow your lawn to protect itself by going dormant.
You can then wait for water restrictions to ease and give it a good drink as fall arrives.
And don’t worry, dormancy is a natural process and isn’t harming your lawn (provided it doesn’t persist beyond six weeks or so, that is).
Check out this article on identifying if your grass is dormant or dead, so you can figure out your next course of action without flying into a panic!
Alternative Methods for Preventing Lawn Stress
Aside from watering, the other things you should do to look after a heat-stressed lawn are actually more about what you shouldn’t do.
With your lawn under a lot of pressure already, trying to adapt and see itself through the season, you certainly don’t want to add to its problems.
Things that can stress a lawn include lots of foot traffic, frequent, short mowing, and use of lots of lawn furniture, toys, or other features placed on your lawn.
If you can keep off your lawn as much as possible, wait longer between mows, and give your lawn room to breathe, then you’re giving it the best chance of coming out the other side unscathed.
What if I See No Improvement?
The caveat to all this advice is that your lawn may already in fact be dormant.
This is especially likely if you’ve been away on vacation and weren’t present to witness the slow descent into a heat stressed state and then, ultimately, dormancy.
If your lawn is already dormant, then the best way to look after it is actually similar to caring for a heat stressed lawn, except you will water a little less.
Unfortunately, it won’t return to its lush green state until temperatures drop and an abundance of water arrives with the change of seasons. But fear not, this will happen!
You shouldn’t necessarily try to bring a dormant lawn out of dormancy if you are experiencing drought conditions with limited water available.
This will likely do more harm than good, not to mention a waste of valuable water.
Instead, you’re aiming for the minimum amount of water possible to stop your grass from dying completely. Experts recommend around ½ inch, once per week.
How to Prevent Heat Stress in the Future
There are some things that make a lawn more susceptible to heat stress.
If you can avoid these things and instead do things to promote the health of your lawn, then it should be more resilient come summer, and better able to cope with heat stress.
A tight, compact lawn is a big contributor to heat stress because it limits the amount of water that the roots can access.
Making sure your lawn is well aerated prior to summer will help a lot to prevent heat stress.
If you’re new to aeration, no problem! I have a complete guide to aeration here, and you can find all the different types of aerators at that link.
On a similar note, dethatching can be just as helpful as aeration in helping your lawn to stay healthy, so add this to your pre-summer lawn care job list!
Remember, though, a thin layer of thatch is actually going to be beneficial for your lawn, as it will help protect it from the beating sun.
With that in mind, it’s important not to remove all of it when dethatching – especially in the spring. Take a cross-section sample with a soil probe. If the thatch is less than half an inch, then leave it alone.
If you’re a bit overwhelmed by all the different lawn care jobs and when you should do them, I have a lawn care calendar that might be helpful.
Raise Your Mower Deck
Mowing your lawn too short can also increase a lawn’s susceptibility to heat stress.
Mowing shorter actually means that you end up with shallow roots. Shallower roots can’t reach down into the soil as far to access moisture that might be present deeper in the ground.
This means that when a period of dry weather arrives, your lawn won’t last as long before it starts to get heat stressed.
Instead, mowing longer encourages deeper roots, which means your grass has access to more moisture for a little longer.
Are you in the market for a new lawnmower, or not sure whether you’re using the right kind for your yard? I have an article dedicated to different lawnmower types that you might find interesting.
Avoid Over Fertilizing
What? Surely fertilizing your lawn is a good thing?
It is, but only at certain times of the year. The general rule of thumb to remember is to only fertilize your lawn during its active growth phase.
Fertilizing your lawn when it is not actively growing will do more harm than good.
Not only are cool season grasses not actively growing much during the summer, but if they are heat stressed, then fertilizing will only result in more stress!
This is because fertilizer encourages growth at the expense of roots, when what we really need in summer are healthy roots.
You can read more about fertilizing know-how and the different types of lawn fertilizers by following that link.
Should you mow a heat stressed lawn?
Absolutely not! If your lawn is under a lot of stress, then the last thing you want to do is add to its troubles.
Which is exactly what you’d be doing by taking a lawnmower blade over it – not to mention the machine itself, and any wheels/feet that might also be part of this equation.
It’s not rocket science – if your lawn is heat stressed, stay off it as much as possible.
Can heat stressed grass recover?
Yes. In fact, that’s exactly what they’re designed to do. Even if you did nothing, there’s a very good chance the lawn will bounce back.
Unless, of course, it’s a particularly brutal and lengthy hot spell. In which case, the lawn will need all the help it can get. Follow the steps above for some first aid for your lawn.
How do I fix heat stresses in my lawn?
The main way to treat lawn heat stress is proper irrigation. Water deeply, around two to three times a week. Again, here’s a link to an excellent article on how to properly water your lawn.
How do you tell if your lawn is heat stressed?
The weather will be your first clue. If you’ve had cloudless skies, no rain, and baking sun for a few weeks, then there’s a good chance your lawn has taken the full force of it.
A heat stressed lawn is going to look yellow, brown, or tan in color, and be dry and brittle to the touch.
Compact soil can also be a sign that your lawn is heat stressed – so try the “screwdriver trick” mentioned above.
Is my grass dead or dormant?
Good question. Sometimes, after the heat stress of the summer and the cold stress of the winter, you might freak out that the extremities of these seasons have killed off your grass.
This article on dead grass vs dormant grass will hopefully allay your fears, and provide you with everything you need to know either way.
Should I water my lawn every day in extreme heat?
No. I can understand your first instinct is to just lay on the hose and sprinkler system – but that’s going to do more harm than good.
Even in very hot conditions, the rule still applies. Water deeply – but not more than two to three times a week, five to ten minutes at a time.
And remember to water early in the morning, or late in the afternoon/evening, so not as much of the precious H20 is lost to evaporation.
Heat stress can be a problem for lawns, but there are things we can do to help once this issue is recognized.
I hope this article has helped you identify the signs of lawn stress, and all the steps you can take to help ensure your lawn is as healthy and resilient as possible when the hot weather sets in.
And please feel free to reach out with any of your top tips for lawn care in the comments.