Name: Becky G.
Date: Saturday, June 01, 2002
We live in the midwest and have a problem with earthworms
crawling into our swimming pool. Why do they do that? After a really
bad rain we can have over a hundred, but in the morning following a dry
night we'll have about 10. Is there any thing that we can put along the
border that will make them stop crawling to the pool?
I am sorry that I cannot tell you how to keep the earthworms out of your
I can tell you that earthworms come to the surface at night, especially
after rain soaks their underground burrows, and they may go to your pool
because they are attracted to the water, or maybe just crawl in by accident.
Maybe a pool maintenance or supply company could help you with keeping them
Long periods of rain or very water soaked soil will bring the
earthworms to the surface. The reason seems to be related to
the fact that they breathe
through their skin, and the process of diffusion of oxygen is not
efficient enough when the ground is soaking wet. Water does not
hold the amount of oxygen as does the air. Earthworms need aerated
soil for this reason; they actually help aerate the soil with their
continuous tunneling. When they get to the surface under these very
wet conditions, they often find that their is a great deal of water
on the surface as well and they tend to move around probably seeking
drier areas for better oxygen diffusion, it is believed. There have
been some studies to confirm this idea.
Now when they move around they do not have anything but the ability
to detect light. Light is something they avoid. During the daylight
period, this may add to the reason they move around; seeking a dark
area. Daylight is a dangerous thing! Remember the early bird gets
the worm? Earthworms normally come out at night for it is dark, they
mate on the surface exclusively because it is difficlut to find mates
underground. Normally, however, you will not find the earthworm moving
around to any great extent at night.
I have no idea how your swimming pool is designed. I would hypothesize
that it does not have a lip around the perimeter of the pool for these
worms would have a difficult time climbing over it. The pools in my
area do not see earthworms because they all have this feature. If you
do, then there is something else involved.
You could purchase from a garden center some rounded edging that would
help this situation.
Now, there is one thing you must re-think. Earthworms are as far as
being a pest as a organism can be. They are very helpful in providing
nutrients to the soil, help increase the amount of soil and serve by
their presence to indicate that the soil environment is in good condition
I hope I have helped.
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Update: June 2012