Ask A Scientist© Zoology Archive

name         Aswin
status       other
age          30s

Question -   Lawn and Earthworms:

I think my soil is somewhat compacted. Instead of aerating my lawn
conventionally, I would like to buy and use earthworms instead. I read
that the "nightcrawlers" worms are deep-burrowers. They build large,
vertical, permanent burrows that extend 5 to 6 feet deep or more. Other
earthworms such as (redworms, grayworms, fishworms, etc) only work the
top 12 inches of soil.

My fist thought was the deeper the better so I thought the nightcrawlers
should be used. But then I also read that these nightcrawlers (unlike
other earthworms) they construct middens over the mouth of their burrows
thus leaving a surface residue. I don't know how big or small so I'm
concern with the appearance.

I wonder if you can give advice as to what I should do. A) forget the
worms and aerate using a machine B) use other shallow-dwelling worms that
don't leave any residue or C) go ahead and try the nightcrawlers worms.

Hi Aswin,

Grass roots generally don't run very deep, so unless you have a severe
drainage problem or want to help your trees deeper burrows won't make much
of a difference.  I would go with shallow worms first.  If you get your
lawn chemically treated (insecticides, herbicides) you might want to ask
what they do to the worms; I would think in general the less treatment, the
better off they'll do, even if your lawn might not be putting green perfect.

Don
Donald Yee Ph.D.                San Francisco Estuary Institute
180 Richmond Field Station,     1325 South 46th St. Richmond, CA  94804


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