How Does Trampling Harm Grass?

By Danit Brown

Posted December 13, 2016

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A macro shot of the tops of blades of grass. They're bright green. The background is blue-green and out of focus.

You've probably seen signs asking you to stay off the grass. You may have wondered what's the big deal, it's just grass.

And in some ways, you're a little right. Even if you harm the blades of grass, the parts of the grass that are responsible for new growth are at the plant's base. That's why you can mow grass without killing.

What does damage grass is walking or driving on it with enough force that the soil is compacted. Compaction can reduce the amount of air and water available to a plant.

When it rains on compacted soil, the water runs off instead of being absorbed. Even worse, water can sometimes puddle and drown the plant.

So, how does grass on football and baseball fields stay so green and healthy, despite all the heavy traffic it endures? Actual grass field are often planted over a layer of sand, which greatly reduces the problem of compaction.