Why Do Earthworms Come Out After a Rain?

Most people think that earthworms come out of the ground after a rain because their burrows are flooded with water.

But earthworms aren’t afraid of water; they can live completely submerged in water for many months, and in fact, die if their skin becomes dried out.

What worms are actually afraid of is waterlogged soil, for it contains a substance called carbonic acid, which forms when water combines with certain chemicals in the soil.

Carbonic acid enters the worm’s body through openings in its skin and acts like a drug on the worm, eventually even killing it. So it’s carbonic acid and not water that sends earthworms scurrying out of the ground after a rainstorm.

About Karen Hill

Karen Hill is a freelance writer, editor, and columnist. Born in New York, her work has appeared in the Examiner, Yahoo News, Buzzfeed, among others.

6 thoughts on “Why Do Earthworms Come Out After a Rain?”

  1. So why did I just see many earthworms energetically moving around on our sidewalks and patio DURING a heavy downpour? Nothing I’ve found online explains this.

  2. That is the reason. They don’t mind the rain itself but the carbonic acid that forms with the soil. Therefore they don’t need to get out of the rain just the soil and that acid. Side walks don’t have the proper elements to form carbonic acid so they are safe (excepting booted feet of course). Acids reacting with H20 don’t take very long so as soon as the rain penetrates the topsoil it would be a problem.

  3. So it’ll be safe to put the earthworms back to the surface of soil after the rain stops? I often do this because it’s hard to watch them wiggle helplessly on the sidewalks and be killed by the many “booted feet”.

  4. Is there anything I can sprinkle around my concrete patio so worms won’t come up on it when it rains? Hundreds of dead dried on worms left after the rain.

  5. The earth worm only come’s up when it rains because theyre barrels get floded…………scientist test this fact by benoculatin

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