are my onions going to the worms?

General    zone 4

I came out this morning to check on the garden after a chillier than expected night. What I found was something that has been driving me crazy, onion sets laying out on the ground! Not just out of the ground but a few inches from where they were planted, with some of the tops disappearing down what looks like a worm hole! Now I love having these little wigglers in my garden and I go out of my way to mix in all sorts of yummy compost and leaf litter just for them to snack on so I'm hoping they're not really to blame but if the shoe fits....

Posted by: J.D. Archer (31 points) J.D. Archer
Posted: April 24, 2013


Unfortunately, I think it may well be the worms that are doing this. Lumbricus worms such as L. terrestris are not native to the US, they were introduced from Northern Europe. Unlike most other earthworms, Lumbricus worms come to the surface to feed. They will also drag leaves and other plant debris to the mouth of their burrows and allow them to decompose before consumption. Although they are beneficial to the soil, they will occasionally cause damage to young plants and seedlings by uprooting them.

There has been a lot of research done on the effect of introduced earthworms on native forest ecosystems. Below you will see an image which shows the same sugar maple woodland before (top) and after (below) invasion by European earthworms. This image is from a paper published in the journal Biological Invasions (see image for full reference). You can clearly see that the worms alter the structure of the ecosystem on the forest floor and they are capable of uprooting young tree seedlings.

What can you do? The benefits of these worms in your garden greatly outweigh the negative and act as a good indicator as to the health of your soil. Try mulching around the onion sets with layer of grass clippings or leaves to distract the worms from the onions. From your question it seems that you have compost and leaf litter incorporated into your soil, but this likely hasn't been a solution as these worms feed at the surface. A layer of organic mulch on the soil surface will provide a (tasty) physical barrier to the worms and hopefully give your onions respite enough to get their roots established so that the worms can’t pull them up anymore.

Posted by: Lindsay McMenemy (2 points) Lindsay McMenemy
Posted: April 25, 2013

J.D. Archer commented,
Thanks for the great info on earth worms, guess it's time to mulch :)
over 7 years ago.

Lindsay McMenemy commented,
No problem - hope it helps!
over 7 years ago.

It isnt shrews or voles, failing that it reminds me of the bugs bunny cartoon where he has a tunnel under them and pulls them down! Birds can pull them out but they wouldnt pull them under ground more investigating me thinks

Posted by: cathy barker (3 points) cathy barker
Posted: April 24, 2013

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