Does Watering Grass In The Sun Burn It?

Whether you’re taking care of your own lawn or you have been doing lawn care professionally for a long time, your goal is likely to create conditions that allow for your lawn to grow and flourish to its fullest capacity.

The last thing anyone wants is dying grass, diseased patches, or a completely dead and unsightly lawn altogether.

When it comes down to cultivating the perfect lawn, it can be a bit more complicated than the “soil, water, and sunlight” method. In fact, a lot of work, time, and research goes into learning to adequately care for a lawn.

In this article, I will seek to answer a specific question that many people who care for lawns commonly have, which is, “Does water grass in the sun burn it?” Although the answer to this question may at first seem intuitive to some, it’s actually a very commonly disputed question.

With so many factors affecting the health of lawns, it can be difficult to isolate and identify exactly what is causing dying grass. To learn more about the answer to this question as well as more tips on related lawn care, keep reading.

The answer is no, water will not cause the grass to burn, no matter the amount of sunlight. In fact, watering will make grass grow healthy even if it’s provided with water during the hottest, sunniest hours of the day. 

Now that we’ve identified the short answer, let’s take a look at where this myth came from and delve into how it was determined to be a myth.

Check out my article on the best sprinkler systems for your lawn.

Where does the misconception of water causing the grass to burn come from? And why has this idea been determined to be a myth?

It is relatively common for people to question whether or not grass can be hurt by watering it during the middle of the day.

This theory rests on the idea that water magnifies the sunlight, causing it to affect the grass more intensely, similar to how it’s easier for people to get sunburn when next to bodies of water. However, these two processes do not work the same way.

The theory of water droplets causing sunburn on plant life has been proven false by science-based experiments.

In 2010, Richard Gray, Science Correspondent, lead a discussion surrounding this topic in the Telegraph UK in an article titled, “Sunburnt plants ‘myth’ is debunked.”

In the article, he explains how a team of physicists, using both computer models and live plants, proved that water droplets on plants could not effectively magnify the sun’s rays fast enough to cause damage before the evaporation of those water droplets.

This article can still be found on the UK Telegraph’s website.

In accordance with their findings, plant burns are caused not by sunlight magnified by water droplets, but instead by other harmful agents. So, while thinking about the best way to take care of your lawn, you will be best served to look at other factors than the magnification of sunlight by water droplets.

Let’s discuss what else may be contributing to “burnt” grass.

Check out my full article on making yellow grass green again…

What other factors commonly contribute to dying grass?

A dying lawn or dying patches of grass that may appear “burnt” may be better thought of as under-hydrated. Under-hydration is a phenomenon that can be prevented if carefully observed and accounted for beforehand.

There are a few things that commonly contribute to grass being under-hydrated, including:

• Salt build-up: Salt build-up can be a vicious cycle caused by previous lack of water, poor soil quality, or using a water source that contains trace amounts of salt, causing excess salt content every time the lawn is watered.

• Over-fertilizing: Over-fertilizing is another common contributor to when it comes to dying grass. Salt content as well as the content of other chemicals in fertilizer tend to be higher than is good for lawns when used in excess amounts. While fertilizer is helpful in small amounts, too much will damage your grass, especially if your lawn isn’t being periodically and adequately flushed.

• But fear not, if your grass has turned yellow from over-fertilizing, it can still most likely recover. Brown grass, however, may have a harder time recovering. As a general rule, it’s a good idea to start with the smallest amount of fertilizer you can and slowly increase the amount from there.

• Small amounts of chlorine, acid rain, or other pollutants may also be contributing to dying grass.

In addition to these factors, the time of day can affect how healthy your lawn is (but, remember, not because of the magnification of sunlight by water droplets).

Check out my article on advanced to basic mowing techniques I actually use.

What is the best time of day to water your lawn?

• Morning: Morning (before 10 am) is widely considered the best time to water your lawn on a consistent basis so that it can become adequately hydrated and stay cool enough to withstand the heat of the day. It also helps that wind and sunlight are at a minimum in the morning, so the water is less likely to evaporate or get blown away.

• Mid-day: While watering during the middle of the day isn’t always a bad thing, especially on hot days when the grass needs more water than normal, watering during the middle of the day can be less efficient because of the tendency for water to evaporate during this time of day. So, to prevent wasting your water resources, only water grass during the middle of the day when absolutely necessary.

• Late afternoon: Watering your grass in the late afternoon is a second-best alternative to watering it in the morning. This time of day can work well if you forget to water in the morning, however, you shouldn’t water your grass too late in the day.

• Night: Avoid watering your grass late at night to lessen the risk of your lawn from becoming diseased. Fungi and other small organisms are attracted to water even more so in the absence of sunlight. And while some fungal growth can be an integral part of a healthy lawn, you may not want fungi growing all over for aesthetic reasons and because not all fungi are healthy for lawns.

Finally, let’s look at some other tips to keep your lawn as healthy as it can be:

Determine how much water your grass needs: Grassroots tend to go about 6 inches down, generally. To ensure that water reaches the bottom of the roots but does over-hydrate them, the general rule is to give the grass at least 1 inch of water at the surface level.

You can easily check for this 1 inch of water on the surface by placing a can on your lawn before watering and check for how much water has built up inside it after the grass has been watered.

To check how far down the water is going, you can stick a tool like a screwdriver down into the soil, just like you would stick a knife into a cake pan. If it goes all the way down easily, the water likely penetrated that deep.

Choose the right kind of grass for your climate: If you’re growing your grass from seed, you need to be sure to choose the right kind of grass for your climate. While getting a local opinion is always the best option, you can also easily search online to find out what kind of grass grows best in your region and climate zone.

Some types of grass may require more care in certain areas and be more resilient in others.

Never cut more than 1/3 of your grass down in 1 cut: Cutting your grass too short can make it less resilient and cause it to die quicker, for the same reason that cutting a tree down (rather than trimming the branches) will prevent it from growing again.

Instead of “cutting” grass, you can instead think about “trimming” it.

Try using mulch clippings in addition to fertilizer. Mulch clippings can provide essential nutrients like potassium, phosphorus, and nitrogen for microorganisms in the soil to break down and use.

Check out my full article on why you should mulch your grass clippings.

When you first begin experimenting with your lawn, it’s always better to change one thing at a time in order to isolate the effect of what you’re changing. By doing this, you’ll get a better idea of how different factors affect your lawn.

Remember, every lawn, grass, type, and climate is different and learning to cultivate the perfect lawn takes time.

I hope this article has given you some valuable information regarding what does and does not contribute to the health of your lawn. In particular, I hope that you’ve come to understand the myth concerning watering your lawn in the middle of the day and how watering grass in the sun does not burn it.

While local knowledge can be a huge asset when it comes to lawn care, sometimes it’s best to look to outside sources as well, like experienced lawn care specialists or scientists to answer the big questions.

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