Have you ever heard that you should not water your lawn during the heat of the day because it will scorch the grass? In a move straight out of Mythbusters, Gabor Horvath, from Hungary's Eotvos University set out to test this.
He and his team found that water droplets sitting directly on smooth leaves had no effect. However, if the leaf had tiny hairs, the droplet could be held above the leaf by the hairs. In that case, the water droplet acted like a lens, focusing the sun’s rays and causing leaf burn.What does this say about watering lawns? I went out with a low powered microscope to examine the grass on my own lawn. None of the grass blades I examined had any visible plant hairs, but some interspersed clover leaves were covered in them. Depending on the makeup of your lawn, you might well be better off to avoid watering it during the heat of the day.
transpiration is the main issue here, Kathy, and it's common sense, really, since it is hard to find lawns that are yellowed from tiny little light foci!
ReplyDeleteI've hear this argument before. The botany is right, for sure, but the logic isn't?
You're absolutely right. In fact, the authors of the study say they think it's extremely unlikely that this lensing affect could be responsible for fires or other damage. I still think it's an interesting finding though.
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