Laidback Gardener Tip of the Day

Warning: Eggshells Actually ATTRACT Slugs

This is a repeat, somewhat updated, of a tip covered last year. If you’ve already read it, sorry, but I received several questions on the subject lately and figured it was worthwhile repeating.

20150714DA very popular gardening myth claims that coarsely crushed eggshells are very sharp and that slugs would tear their bodies open trying to cross them. Therefore, by surrounding a plant susceptible to slug damage with a ring of eggshells, you can protect it, because no slug would dare try to cross such a barrier.

In reality, however, the slugs secrete “slime” (mucus) precisely to protect against cuts on rough surfaces. This slime is so efficient they can even cross shards of glass without any damage. Lots of studies have been made about slugs and eggshell barriers and the conclusion is clear: slugs will cross an eggshell barrier as if it weren’t there and without suffering any damage whatsoever.

Until recently, though, it was simply thought that eggshell barriers were not effective. But it’s worse then that. Eggshells, unless thoroughly cleaned to remove the inner membrane and rinsed to get rid of any remaining albumin (egg white), give off an odor that will actually attracts slugs! So “eggshell barriers” are not only ineffective, they actually make things worse.

I highly recommend you visit this website: www.allaboutslugs.com/eggshell-myth-busted/. It’s an excellent source of slug info. Here are some photos from the site I’ve used to illustrate the situation. I’ve added arrows to make things clearer.

PHOTO RADAR FOR SLUGS

Set-up: 2 lettuce leaves are placed on the ground at night.

After about an hour:

20150714AA first slug arrives at the egg shell “barrier” and starts to investigate.

About 45 minutes later:

20150714BSeveral slugs have located the leaf surrounded by shells and are starting to chow down. They have not yet found the unprotected leaf.

The next morning

20150714C

The “protected” leaf has entirely disappeared. The leaf not surrounded by shells is in better shape, but has also suffered damage.

Another Garden Myth Debunked… But Many More to Go!

The information above is not new: experts have been telling gardeners for decades that eggshell barriers don’t protect plants, but gardeners seem to prefer believing in myths rather than facing reality.

Here’s my warning for gardeners everywhere: just because “everyone says it’s true” doesn’t mean it really is true! If in doubt about a gardening technique, check with a reputable authority to make sure it really is effective.

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

3 comments on “Warning: Eggshells Actually ATTRACT Slugs

  1. Pingback: Slug Treatments that Really Work! | Laidback Gardener

  2. Pingback: Beware of Garden Myths! – Laidback Gardener

  3. Pingback: Garden Myth: Eggshells Are a Good Source of Calcium for Garden Soils – Laidback Gardener

Leave a Reply

Sign up for the Laidback Gardener blog and receive articles in your inbox every morning!

%d bloggers like this: