If you are experiencing hot weather or drought conditions, your first instinct may be to water your lawn if water is available for that purpose. This isn’t necessarily wrong, but we’ve all heard at some point or another that watering grass in the sun could damage it. Is that true or can you water grass in the sun with no ill effects? Is there any way to ensure no damage is caused if you water your lawn in the sun? You can find these answers, and more, below.
Does Watering Grass in the Sun Burn It? (The Short Answer)
No, watering grass in the sun should not burn it. However, there may be some truth to this myth as water that is acidic, chlorinated, salty, or that forms droplets on horizontally oriented blades of grass can cause this type of damage when applied during the sunniest part of the day.
Where the Hot Weather Watering Myth Comes From (The Theory)
The myth about watering your lawn in the sun leading to burnt grass likely stems from pure coincidence. The day is hottest when the sun has been out the longest. If you are in an area experiencing drought-like conditions, your lawn will likely turn brown or yellow even if it does get a bit of water once in a while.
This does not mean that the water is causing the browning or that the water droplets are producing a “magnifying glass effect” and enhancing the rays of the sun, thereby burning the blades of grass.
However, this myth may also stem from another coincidence. In the study that disproved this myth, smooth tree leaves that are held horizontally to the sun can catch water droplets and may be burned by the sunlight passing through them.
The same is true for ferns with hydrophobic wax hairs as these hairs, like the flat leaves held horizontally, hold the droplets at just the right angle to intensify the sunlight and cause damage.
As most turf grasses hold their blades upright, especially if they are mown regularly, water droplets are unlikely to cause an issue for these plants.
Can You Water Grass in the Sun? (+ Should You?)
Yes, you can water your grass in the sun, and doing so is better than watering your grass just after the sun has gone down. However, if given the choice, you should water your lawn as early in the morning as possible. Any time from an hour before sunrise to an hour after sunrise is the best time to water your lawn.
The worst time to water your lawn is an hour after sunset with a close second being during the hottest part of the day (around 2 PM, depending on the time of the year). This prevents water waste due to evaporation.
If, however, your lawn is exhibiting signs of heat stress and it is unusually warm, apply more water if you are able. Not much water is needed, just run the sprinklers for a minute or two. This should help prevent excessive browning, though much of this water will be lost to evaporation.
I would not recommend using this strategy regularly as it can encourage the grass to retain less water over time.
The Truth in the Myth: When Watering Your Grass in the Sun Can Burn
Does watering grass in the sun burn it? Not outright or in most common situations. While more recent research suggests that watering your lawn won’t burn it and that the “magnifying glass effect” has not been proven, that doesn’t mean watering during the sunniest part of the day doesn’t come with risks. The answer to “Is it okay to water grass in the sun?” comes down to what’s in the water.
For example, even lightly chlorinated water can cause your grass to be susceptible to damage and burns when exposed to sunlight. This can even apply if you water your lawn in the early morning, as we suggest. The same is true of salty or significantly acidic water.
If you must use any of these types of water on your lawn, do so as early in the day as possible to help prevent damage. Sunlight really will increase your risk of burnt grass when combined with these types of water.
Watering Grass in the Sun: Why This Isn’t the Best Time Under Normal Circumstances
It’s perfectly fine to water your lawn while the sun is out if it’s in the early morning and there is still dew on the grass. However, it’s rarely optimal to water your lawn in the afternoon each day unless your lawn meets very specific criteria.
For example, professional golf courses in hot and dry regions will water their greens in segments for 1 to 2 minutes up to 3 or 4 cycles a day. This keeps the grass uniform all day and prevents dry grass from causing problems for the golfers. On the flip side, the grass will then be more likely to keep less water in reserve and may be more susceptible to damage due to sudden drought.
For the average lawn, under normal circumstances, the best time to water your lawn is always in the early morning, up to an hour before sunrise. In most regions of the USA, watering your lawn at around 5 am each day is optimal.
This helps prevent issues caused by watering your grass at night, reduces water loss due to evaporation, and prevents any possible damage that watering in the sun could cause if you are using chlorinated water or water with a high salt content.
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