Coles County Yard and Garden

Coles County Yard and Garden

Benefits of Eggshells

By Darla Chouinard, Master Gardener

A couple weeks ago, I attended the Gardening Insights event in Decatur. One of the classes I attended was on growing great tomatoes. Most everyone in the class "won" a special tomato garden additive, a small peanut butter jar with ground up eggshells and dried coffee grounds. The Master Gardener educator, Richard Zerfowski, said that eggshells and coffee grounds are helpful at preventing blossom end rot in tomatoes. Eggshells contain Calcium Carbonate.

According to an article by Jennifer Schultz Nelson, blossom end rot is caused by a calcium imbalance within the plant. It is common when the growing season starts out wet then becomes dry - when fruit is setting. It is not a disease. It is a physiologic condition caused by extreme moisture swings in soil. Wet to dry soil will disrupt the movement of calcium in plants. Tomatoes are not the only garden produce that gets blossom end rot.

Not only can eggshells benefit plants, but they can also benefit animals as well. I have saved and ground-up 15 pounds of eggshells to put in my gardens and to feed to my worms (red wigglers). Worms do not have teeth so they ingest sharp gritty substances like sand and crushed egg shells to enable them to "chew" the food in their crop. Their crop is like a stomach. Eggshells are good for worms, and worms are great for our soil.

It is a common misconception that eggshells can be put around plants to keep slugs from decimating garden plants and hostas. Unfortunately, it is not effective. For proof that it doesn't work, you can watch videos on YouTube of slugs crawling over crushed eggshells to eat lettuce.

As Master Gardener Youth Gardening Committee Chair, I find different ways for kids to start plants. One commonly suggested method (that is not my favorite) is by cracking the end of an eggshell off, poking a drainage hole in the bottom of the "egg cup", and placing potting mix and seeds inside. When your plant is large enough to transplant, place the transplant, shell and all, in your garden. This is a neat idea for a quick and easy seed starting set-up. However, eggshells hold a scant amount of potting mix and don't allow for much root growth prior to transplanting. Also, the soil inside the shell dries out pretty rapidly. If you chose this method, I would suggest carefully breaking the shell to allow the roots to grow. Eggshells don't break down very rapidly, so for better absorption break them into tiny pieces.

The Youth Gardening Committee recently met with Douglas Hart Nature Center's Nature Nuts. We made a decoupage project, with pretty flower pictures from magazines and catalogs, to Mod-Podge them to wood picture frames. I supplied pressed leaf prints for the kids to finish their picture at home.

This month, we will be teaching at the DHNC open house on March 24th. We will be planting an Easter Basket for the kids to take home. So, please bring your kids/grandkids to the open house between 8:00 and Noon.

If you have other questions about your garden or landscape, feel free to contact a Master Gardener volunteer at the University of Illinois Extension office in Charleston at 217-345-7034. You can also check out the many horticulture webpages at the U of I Extension's website by visiting . And be sure to like the Master Gardeners' Facebook page, at

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