Wet Plants Feel the Burn

A study in the journal New Phytologist confirms the gardener's belief that droplets of water resting on some types of leaves can focus sunlight until the plant's surface actually burns. Karen Hopkin reports

Illustration of a Bohr atom model spinning around the words Science Quickly with various science and medicine related icons around the text

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


If you’ve ever had a garden or grown flowers in a window box, you’ve probably heard that you shouldn’t water your plants at high noon because their leaves might scorch. Now a study in a journal called New Phytologist confirms that water droplets can focus sunlight to the point that it burns, a finding that applies to plants and to people.

Check any gardening blog and the question of whether water can burn comes up with some regularity. But the problem had never been thoroughly tested. So scientists at Eotvos University in Budapest decided to do just that. And they found that the results depend on how hairy you are.

On leaves that are really smooth, like those from a maple tree, water doesn’t do much damage. But leaves that have tons of tiny hairs, like a fern, can hold spherical water droplets in focus above a leaf’s surface. Those drops act like mini magnifying glasses, focusing the sunbeams on an area that will subsequently fry.

And the same is true on you. Cooling off in the pool might seem like a stellar idea. But the resulting water droplets, propped up by your body hair, poolside, could turn you from lounger to lobster.

—Karen Hopkin

[The above text is an exact transcript of this podcast.]

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe