Can Grass Catch on Fire from the Sun (And Also what Temperature?)

Have you ever burned ants with a magnifying glass and wondered if sunlight could do the same to grass? The short answer is yes, it can, but how do you turn the sun upon your lawn? This article will detail what you need to know about setting your grass ablaze—responsibly.

Why You Should Set Srass on Fire?

One of the best questions about setting grass (usually clippings, but sometimes entire patches of lawn) on fire is “why would anyone do that?” There are a few reasons to consider torching your lawn. Let’s look at the why before the how.

The most prominent reason to set your lawn ablaze is to make weeding easier. If you have a patch covered in weeds, why not burn it all? It doesn’t require any additional chemicals. Unless you have particularly toxic weeds, burning them is usually safe.

Another major reason to burn the ground is to encourage diversity in your yard. Burning is usually effective at leaving fertile soil behind if you want to remove weeds and plant something else. Furthermore, if you like having furry friends like squirrels and rabbits in your yard, they will feel more welcome in areas without tall grasses.

Finally, burning your lawn can lead to richer soil. The reason burning plants leads to fertile soil is something called “biochar.” Burning plants leaves carbon, basically charcoal, behind. However, the ash may alter the pH of your soil, so keep that in mind. Some people also turn their grass clippings into biochar for similar purposes.

This article will discuss safe ways to burn your lawn farther down. We now know the why, so how can grass be set ablaze?

What Temperature Does Grass Catch Fire?

How easy is it to set your grass on fire, anyways? It depends on if your grass is wet or dry, whether the ambient temperature is hot or not, and if it is humid outside. If it’s cold outside, the grass is fresh, and the air is muggy, it is a bad day to light up your grass. But if it’s sunny and dry, and there’s a lot of dead grass around, one glass bottle can set your entire lawn ablaze.

But if you want to be precise, dry grass requires temperatures above 135 degrees Fahrenheit to start burning. The better general estimate is 300 degrees Celsius. That’s above the temperature of boiling water, twice the amount of heat required to pop a bag of popcorn, and hotter than most ovens.

Can Sunlight Set Dry Grass on Fire?

Imagine you had a lawn party in the summer. There was booze, barbeque, and maybe cigarettes. This is the perfect time for your lawn to catch fire, and all those things can turn your yard into a bonfire if you are not careful!

But one of those things is not like the others. How can a beer bottle set your lawn on fire? It’s the same method as burning ants with a magnifying glass: the glass focuses sunlight just enough to burn the grass. Again, this is easier if the air is hot, and the grass is dry.

Likewise, if you water your plants at the wrong time or place (aim for the roots, not the leaves), sunlight may scorch them.

Can Fresh Grass Catch Fire?

If you must, you can also set fresh grass on fire. However, due to the moisture in the grass, it is harder to ignite than dry, dead grass. Sunlight and lightning are both hot enough that they can burn wet and dry grass.

Can Cigarettes Set Grass on Fire?

Yes, cigarettes can set your lawn on fire, especially if the grass is dry. A stray cigarette butt is unlikely to set wet grass on fire. If chemicals such as oil and gasoline are present, the grass is more likely to catch fire. Please treat things such as disposable barbecue pits and lit chunks of charcoal with similar caution.

Can Lightning Set Grass on Fire?

Finally, you may wake up to an unpleasant bald patch on your lawn after a thunderstorm. An errant lightning bolt can set entire forests on fire. Lightning can reach a massive 53,540 degrees Fahrenheit—that’s hotter than the sun, and more than enough to send your lawn (and more) up in flames.

How Do I Set Grass on Fire Deliberately?

We’ve covered most of the ways to accidentally set your grass on fire. But there are also several ways to set your garden or lawn ablaze without harming the rest of your lawn (or anything else).

Your first step will be to mark the area off and remove any flammable materials from the vicinity; this is supposed to be a controlled burn. Also, if you are burning plants aside from grass (like weeds), please make sure that you are not releasing toxic fumes into the air by burning them.

Your next step is to find a suitably sized pane of clear plastic. This method, called “solarization,” weaponizes the beer bottle example from earlier by letting the sunlight bake the area of the lawn we want to burn. This pseudo-greenhouse is particularly effective on raised garden beds, and will also kill worms, insects, and other things that may harm your plants.

Note that solarization is slow. It can take up to 8 weeks for the sun to burn your grass or weeds. Be patient.

The other method of burning your lawn is to use a torch or other source of heat. Burning your plants this way yields more biochar. Do not use harsh chemicals; they can affect the soil. This burn is more likely to spread than solarization, so please be careful. However, this method is faster (and possibly more satisfying) than solarization.


If you were wondering if sunlight can set your grass on fire, the answer is a resounding “yes.” Most of the time, sunlight will accidentally burn your lawn. But you can also use sunlight to kill patches of weeds or grass via solarization. This can be an effective way to kill weeds, worms, and bacteria that could harm your new crop. Most natural forest fires start with lightning strikes, but solarization—or a torch—is the next best thing.

Also Read

Does Gasoline Kill Grass and Weeds?

Does Roundup Kill Grass?

Will Lime Kill Grass

Does Human Urine Kill Grass?

Will Lemon Juice Kill Grass


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