How to Grow Grass in Hot Weather

Current Heat Drought Map as of 6/28

Lawn care during the summer is sometimes referred to as “100 days of hell”. The stresses on the grass from heat, drought, and humidity are often enough to send the lawn into dormancy. 

Steps to Hot-Weather Lawn Care

Step 1: Water Your Lawn Early in the Day

The high dew points that often accompany heat in the summer are often oppressive for people, but they can be downright dangerous for lawns. 

If the air is humid, the grass is going to stay wet for longer periods after a summer rainshower or irrigation session. The leaf blades cannot dry as quickly as they would in the Spring or Fall.  And the combination of moisture and heat is a breeding ground for disease and fungus. Pythium blight is an example of one disease that often develops when night temperatures exceed 65°F in cool-season turf and leaves are continually wet for several consecutive nights. For this reason, severe Pythium blight in cool-season turf is usually found the morning after a late afternoon or early evening thunderstorm in the summer.

To prevent your grass from being wet for too long, try to run your sprinklers in the early morning hours if you are able. This gives the lawn all day to dry off before nightfall. 

And if there's an afternoon rainshower that will leave your grass blades and you cannot avoid your lawn being wet, use it as an opportunity to run your sprinklers and get in a good soaking. Yes, this runs contrary to the previous advice, but your lawn will be wet going into night time anyway, so you may as well use it as an opportunity to give your lawn a good drink - a full half inch of water or more. This will save you from running the sprinklers another day. 

Step 2. Water Your Lawn Often in the Summer

Watering is the single most important aspect of lawn care. And lawns need a lot of water in the summer. About 1.5 inches of water per week, to be exact. Unlike spring and fall, you cannot count on rainfall to get you most of the way there. Weeks can pass without any measurable rainfall during the summer, and even just a few days of temps above 90' and no rainfall is often enough to send your lawn into dormancy.  So it's important to make sure you increase the frequency, water about 3 days a week and get about half an inch per water during each session.

Step 3: Don't Fertilize Your Grass During the Summer Months

This is often the piece of advice that confuses people the most, but the heat and humidity also has an effect on how you approach lawn fertilization. Cool season lawns are growing slowly or not at all during the summer. Just like people do in the heat, they're trying to conserve water and energy. They don't try to push top growth, and instead put most of their energy into growing the root system to drive deep in search of water. 

Fertilizing with a high dose of nitrogen is a shock to the system. It tells the grass to grow, and grow quickly. 

In the summer, your grass is running a marathon. It only needs a few sips of gatorade now and then to make it through. But giving your lawn a heavy dose of nitrogen is like asking it to eat a steak halfway through. This is harmful for cool season lawns in summer, can will lead to diseases which could wipe out your lawn in a matter of hours.

The gatorade in this analogy is liquid bio-stimulants that drive root growth to help it stay alive in the summer heat. Specifically, a mix of Sea Kelp and Humic Acid is all your lawn needs in the summer to stay healthy and alive. 

Step 4: Don't Mow in the Morning or When Your Grass is Wet

When you mow the lawn, you're usually ripping the top of the grass blade - especially if your mower blade is dull. If you mow while your lawn is wet, you're opening up a large surface area for the water to enter the grass blade. This invites a host of diseases and fungus to enter the grass. 

To prevent this, keep your mower blades sharp and do not mow in the morning when the grass is most likely to be wet from either irrigation or dew. Instead, wait until the afternoon, or whenever the grass dries. 

A good rule of thumb is if you see that your mower wheels are getting wet, stop mowing immediately and wait for your lawn to dry out before attempting to mow again. 

Step 5: Understand Water Restrictions

Municipalities will often put watering bans into effect starting in the late spring. 

First, make sure you're clear on the exact language of the water restriction. Read it carefully. Often towns will ban automatic watering, and watering on certain days, but you can still get out there with a hose and water it 'by hand' any time. This is obviously tedious, but you may be able to keep it out of dormancy, so it's important to know if you have to let it go first. 

If your municipality limits watering outright and you're using a public water source, your lawn will likely go dormant during the summer. If this happens, just let it go. Do not mow it, and do not try to bring it out of dormancy by using any product, you're likely wasting time and money. Just stay off it and wait it out.

But there's one thing you can do. Even a dormant lawn needs some water to prevent plant death. If you can just give it half an inch of water per week, even hand watering, that will keep your dormant lawn alive, and it will come back a lot faster when the days get shorter and temperatures fall. 

Below are some most commonly asked questions about maintaining a vibrant and healthy lawn during the summer, and a step by step guide to helping your lawn survive the hot weather in the summer.

Does Grass Even Grow in Hot Weather?

It does, although it grows much more slowly than moderate temps. Avoid forcing too much growth by fertilizing fertilizing with a high amount of nitrogen, as that is the key ingredient to push "top growth". 

Will Grass Seed Grow in Hot Weather?

Much like established grass, grass seed will struggle to grow in high temperatures. But unlike established grass, where air temperature is more important, grass seed is much more dependent on soil temps. Most grass seed will germinate when soil temperatures are consistently between 55-70 degrees. This often coincides with spring and fall, which is why those are usually the preferred season to plant grass seed. By summer most of the country is above 70 degrees in soil temperatures. Further complicating seeding in the summer is the frequent heat waves, which will zap any seedlings that emerge. 

What is the Best Grass to Grow in Hot Weather?

Aside from Warm Season Grasses, Tall fescue is without question the best seed for hot weather. It's the most tolerant to heat and drought stress, and will establish a deep root system which can access water and cool soil temps. Stay away from Perennial Rye or Kentucky Blue Grass varieties if you live in an area that sees consistent 90+ degree days during the summer. 

Can Dry Grass Grow Back?

If its in a state of dormancy, it can be brought back. This requires a significant amount of water, so only attempt to bring grass out of dormancy if your town is not under a water ban, and you have the ability to put out at least a half inch of water on the lawn each day for 5-7 days. 

Growing Grass in Hot Weather, An Easy DIY Approach to Lawn Care

The summer does not have to be game over for your lawn. Lawnbrights plans are specifically designed to keep your lawn thriving through the harshest of summer. Signup for a plan today, kick back, and enjoy your lawn this summer!

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