Three Ways to Use Eggshells for Your Garden (and Three That You Can’t)

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Written By Jim J Neal

There are some good ways to use eggshells in a garden, and some ways that are a waste of time.

What gardener hasn’t said, “Oh, save that, I can use it in the garden!” when looking at all the kitchen scraps we often drop into the trash can without a second thought? Today we’ll focus on one in particular —  eggshells. But beware: Some suggested uses you’ll find on the internet are a waste of time and good eggshells.

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How To Use Eggshells in the Garden

Eggshells contain calcium, an element plants and birds need. But it takes a little help from you and Mother Nature to fashion that calcium into a form they can use.

Add eggshells to your compost pile

Clean eggshells can be added to a compost pile, where they will slowly break down to make the calcium and other elements available.

To speed up decomposition, crumble the dried eggshells into tiny pieces before adding to your compost pile or worm composter. Depending on how small the pieces are and how well your compost pile works, it may still take several years before you no longer see those eggshell fragments.

Add ground up eggshells to bird seed

Birds and chickens need calcium for laying eggs. The National Audubon Society suggests adding crushed eggshells to bird seed mixes. If you do this, clean the eggshells, lay them on a cookie sheet and bake at 250 degrees for about 10 minutes. This kills off salmonella and any other harmful bacteria.

Once the eggshells have cooled, grind them with a mortar and pestle or in an old blender until they look like fine grit. Then mix the ground-up eggshells with bird seed or chicken feed.

Use eggshells as seed starting containers

To use eggshells as seed starting containers, start by carefully cracking open an egg as close to the top as you can, leaving the bottom two-thirds of the shell intact. Then pour out the egg contents to cook as you wish.

Clean out the eggshells and use an egg carton to hold them upright. Punch a small hole in the bottom of the eggshell, then fill it with potting soil or seed starting mix.

Next, sow seeds as you normally would, covering if needed to prevent them from drying out. You may need to repot the seedlings into larger containers in a few weeks because most eggshells aren’t that big. When planting those seedlings in the garden, crush the shell a bit to allow the roots to grow out of it.

It’s admittedly a lot of work to use eggshells in this way, but I did it once to make Easter decorations. I painted the eggshells with faces, then planted wheatgrass in them, which became the “hair” on their heads. After the holiday I tossed them, crushed, onto the compost pile.

Avoid These Suggestions for Using Eggshells in the Garden

Don’t waste your good eggshells on these, which don’t work.

Putting eggshells in the planting hole for tomatoes

Some gardeners toss a few eggshells in the hole when planting their tomatoes to keep them from getting blossom end rot. The thing is, lack of calcium in the soil rarely causes this condition. Skip the eggshells and water tomato plants consistently instead.

Scattering crushed eggshells to keep slugs off your plants

Mulching crushed eggshells around plants like hostas to keep away slugs seems like a good idea, but eggshell pieces aren’t sharp enough to deter slugs. There are better ways to keep slugs off plants, including using diatomaceous earth.

Making eggshell tea for plant fertilizer

It’s a simple recipe: Boil eggshells, then filter out the pieces. But you never know what’s really in that tea and if it will make a difference. It’s better to purchase a fertilizer which clearly lists the elements it contains on the label.

Safety tip: Always remember to always wash your hands and surfaces thoroughly after handling eggshells. Unwashed eggs may have harmful bacteria on their shells.

Carol J. MichelCarol J. Michel

Carol J. Michel
Carol J. Michel is an award-winning author of several books including five gardening humor books and one children’s book. As the holder of degrees from Purdue University in both horticulture and computer technology, she spent over three decades making a living in healthcare IT while making a life in her garden. She started writing about gardening on her blog called May Dreams Gardens which lead to numerous magazine articles, her books, and a podcast called The Gardenangelists. She was recently named a GardenComm Fellow by Garden Communicators International.

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