Do you have dead grass or dormant grass? It can be tough to tell the difference but follow these steps to identify and revive dormant grass.
What Is Dormant Grass?
Dormancy is a naturally occurring period that both cool season and warm season grasses experience, in an effort to conserve water and nutrients. It’s a period of rest during a time of stress which is usually brought on by cold temperatures during the winter, or dry conditions during the summer.
When Does Grass Go Dormant?
It’s important to be aware of when you’re most likely to see grass entering dormancy, remaining dormant, and transitioning out of dormancy. To do this, let’s separate cool season lawns and warm season lawns since the growth calendar is different for these two lawns.
Cool Season Lawns
Take a look at the growth chart of a cool season lawn:
You can see that spring and fall are the times of the year where cool season grass thrives.
During the winter months the climate is too cold in these areas so the grass goes dormant. When soil temps fall consistently below 45 degrees, cool season grass will enter winter dormancy.
During the summer months the weather can be too dry for cool season grasses so a lawn without irrigation will likely go dormant for a short period if there are prolonged dry conditions.
This is the most dangerous period for those without irrigation systems. If you have a long dry spell during this summer dormancy period (more than 3 weeks) your lawn could go from dormancy to dead. It’s this time of year that irrigation systems or trees that block sun are most valuable.
Cool season grass options such as Turf Type Tall Fescue will also buy you a couple more weeks during drought conditions since this type of seed is more drought tolerant.
Warm Season Lawns
For warm season lawns, the hot summer months is when grass thrives. For this reason there is really only one dormancy period for warm season lawns. This period is from fall when soil temps dip below 55 degrees, through late winter when soil temps increase above 55 degrees.
Take a look at the growth chart for Warm Season Lawns:
It’s also important to point out that in warm season lawns, the top goes dormant, while under the soil the roots remain active. This is very different from cool season lawns where the ground gets so cold the roots go dormant as well.
Since roots are still active in warm season lawns during the winter months, they will benefit from being irrigated. They don’t need as much water as during the growing season, but a watering every once in awhile will go a long way.
How Can You Tell if Grass Is Dormant or Dead?
Dormant grass can cause a lot of panic since its tan or brown color closely resembles dead grass, or dying grass. But before you panic, make the following observations and perform the following tests:
1. Irrigate- If you have the option to irrigate your lawn then do so. If it’s early spring, or drought conditions in the summer, you’ll see the lawn green up quickly as it gets a much needed dose of water.
Just realize that if soil temps are still too cold coming out of winter the grass will still be in dormancy and will not green up until soil temps rise.
Look for other signs of spring such as perennials starting to break ground or buds starting to leaf out. If this is happening around you then your grass should start to green up when irrigated.
2. Observe the consistency- Is the brown grass patchy, or uniform and widespread throughout your lawn?
During the winter dormancy period, dormant grass is usually pretty consistent in color throughout the lawn, or through large sections of your lawn. If there are smaller, distinct patches, then you probably have dead grass, fungus, or some kind of other problem in those areas.
For summer dormancy in cool season grass you might see some patchiness since there could be areas of your lawn that tend to dry out quicker due to sunlight exposure and soil makeup. If you have an irrigation system you could have a couple areas of poor coverage and therefor those areas might show signs of dormancy as well.
Overall, dormancy in cool season grasses tends to be uniform, especially during the winter dormancy period.
But for warm season grasses such as Bermuda and St. Augustine, you can get some real funky patterns for the brief periods heading into winter dormancy and heading back out of dormancy in the spring. Don’t be alarmed if you see some of these crazy patterns. Check out this pic of a lawn with Bermuda Grass heading into dormancy:
Even though these patterns are irregular, they should be seen consistently throughout your lawn.
3. Think of temperature and weather conditions- If you see your lawn turning brown think about what the weather conditions have been recently.
Has it been dry during the summer months? Are you coming out of the cold winter months? Is it late fall and temperatures have been really cold, maybe even some mornings of frost? These are all conditions that can cause your grass to go dormant, and therefor will explain the discoloration.
How to Prepare Your Lawn for Dormancy
For winter dormancy…
Applying a late season fertilizer is beneficial. With cool season lawns you want a fertilizer high in nitrogen. For warm season lawns you want a fertilizer high in Potassium with little to no nitrogen.
The last fertilizer application of the season is important for both cool and warm season lawns. To check out more about what you should be doing for your last fertilizer application check out: Winterizer Fertilizer
Also, for warm season lawns continue to irrigate a couple of times a week. Even though the grass is dead on top the roots are still active and need water.
For summer dormancy…
In cool season lawns the best thing you can do is irrigate if that’s an option. That will prevent grass from dying and with enough irrigation it will prevent summer dormancy completely. If that isn’t an option and your lawn is starting to check out the best thing you could increase mowing the mowing height. Leaving grass long will produce shade and help lock in soil moisture. Don’t fertilize, this will cause more stress.
Another thing you can do to help cool season lawns during the hot summer months is to fertilize with higher levels of potassium in late spring/early summer. This will help protect your cool season lawn during drought conditions. But don’t apply potassium if your lawn is already entering summer dormancy. At that point it’s too late and the lawn will only get more stressed.
For warm season lawns, there shouldn’t be much a of a summer dormancy period since warm season lawns like the heat. If you get extreme heat of drought like conditions than irrigating will be the only real way to help out your warm season grass.
Check out more on summer lawn care here: Summer Lawn Care Tips.
How to Revive Dormant Grass
First of all, wait until the time is right. Dormancy is normal and necessary. For winter dormancy wait until soil temps are warming up. For summer dormancy in cool season lawns, wait until the dry spell has ended and your lawn is starting to green back up.
1. Fertilize with organic fertilizer– Organic fertilizers are slow release and non burning. They are a lot more forgiving on stressed out lawns than synthetic fertilizers. Milorganite is a great organic fertilizer.
2. Control weeds- Chances are weeds such as clover and crabgrass have become a problem while your lawn was most vulnerable, especially during a summer dormancy period in cool season lawns. Once the grass starts to green back up it’s safe to use post emergent herbicides to control these weeds.
3. Mow high with sharp blades.
4. Reduce traffic– Do whatever you can to avoid any foot traffic, including dogs.
5. Irrigate– Coming out of winter dormancy is a great time to irrigate both cool season and warm season lawns. In fact, for warm season lawns, continue to irrigate all winter. You don’t need to irrigate as much as during the growing season, but remember, warm season lawns are dormant on top while the roots are still active. The roots will be able to absorb the water and it will benefit your lawn.
For summer dormancy in cool season lawns don’t wait until it’s too late. Irrigate as much as possible even if it means setting up a hose with some sprinklers. Water is the only thing that can nurse your lawn through the summer drought period.
Check Out These Posts Next
The Importance of Soil Temps in Your Lawn
Winterizer Fertilizer: Everything You Need to Know
Top Dressing Lawn: Benefits and Advice
Lime Your Lawn: A Complete Guide
Lawn Dethatching: Everything You Need to Know
White Grubs: Prevention and Treatment
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Thanks for the info. I’m always shocked at how my cool season lawn looks dead after a long winter. But like you said, it always uniform and eventually spring back. I might give organic fertilizers a shot!
thanks for commenting Dan! I’d love for you to give organic fertilizers a shot. They are so much better for building healthy soil and releasing nitrogen slowly and evenly.
Really informative. I never thought to water warm season grass during the winter. Some winters we have little snow for long periods. Very good point indeed!
Thanks very much Alan, happy to hear you found it informative!