Composting with Eggshells 

When you think about composting, banana peels and coffee grounds probably come to mind. But what if I told you that something as simple as an eggshell could be one of your garden’s secret weapons? That’s right—composting with eggshells is an easy, effective, and often overlooked way to nourish your plants, reduce kitchen waste, and even deter some pests.

In this article, I’ll walk you through the real benefits of composting with eggshells, how to prep and use them, and why they deserve a spot in your gardening routine. Whether you’re a seasoned gardener or just getting your hands dirty for the first time, eggshells are a low-effort, high-reward addition to your composting system.

Why Composting with Eggshells Are a Game-Changer for Your Garden

Packed with Plant-Boosting Nutrients

One of the biggest reasons to start composting with eggshells is their impressive nutrient content. Each eggshell contains roughly 2.2 grams of calcium, a vital mineral that helps build strong cell walls in plants. This is especially important for preventing common fruit disorders like blossom end rot in tomatoes, squash, and peppers.

Beyond calcium, eggshells also contain:

• 1% nitrogen

• 0.3% phosphorus

• Trace amounts of potassium, magnesium, zinc, manganese, iron, copper, and sodium

These trace minerals enrich your compost and contribute to long-term soil health. Even better, eggshells have a neutral pH, so they won’t alter your soil’s acidity—making them safe to use in most garden beds.

How to Prepare Eggshells for Composting

Rinse and Dry for Best Results

To get started, collect your eggshells from everyday cooking. If they’re from boiled eggs, you’re good to go. Otherwise, give them a quick rinse with warm water to remove any residue and reduce the risk of salmonella.

Lay them out to dry on a towel or baking sheet. Once fully dried, store them in a reused coffee can, paper bag, or any container that breathes until you have enough to work with.

Crush to Speed Up Decomposition

Whole eggshells can take years to fully break down, but crushing them dramatically speeds up the process. Once your container is full, you can:

• Crush by hand using a rolling pin or potato masher

• Smash with a hammer inside a bag or towel

• Blend them in a food processor or blender for a fine powder

The finer the grind, the faster the nutrients become available to your soil.

How to Use Eggshells in the Garden

Direct Application

Sprinkle your crushed eggshells around the base of your plants as a slow-release fertilizer. If the look bothers you, gently work them into the top layer of soil with a trowel. You can also mix them directly into planting holes—especially for tomatoes and squash—to provide a calcium boost from day one.

Composting with Eggshells

Adding eggshells to your compost bin or pile is another excellent method. They don’t just add nutrients—they help balance the carbon-to-nitrogen ratio and contribute to long-term soil structure. Just make sure they’re crushed first to avoid large, undecomposed shell chunks in your finished compost.

Do Eggshells Help with Pest Control?

You may have heard that crushed eggshells can deter slugs, snails, or even caterpillars by cutting their soft bodies as they crawl over the sharp edges. While this theory sounds promising, scientific studies have shown mixed results—slugs, in particular, don’t seem bothered by them, especially if the shells aren’t rinsed properly.

That said, rinsed and dried eggshells won’t hurt your garden, and composting with eggshells might help discourage some soft-bodied pests. If you’re already using them for nutrients, there’s no harm in trying them as a pest deterrent too.

Addressing Safety: What About Salmonella?

Concerned about bacteria like salmonella? You’re not alone. The good news is that it’s easy to sanitize eggshells before use:

• Rinse with very warm water

• Bake at 130°F (about 54°C) for 20 minutes

This step is optional but offers peace of mind if you’re composting with raw eggshells and plan to handle them frequently.

Is Composting with Eggshells Worth the Effort?

Honestly, yes. Once you make it a habit, composting with eggshells becomes second nature. It only takes a few minutes to rinse and dry them, and the long-term benefits to your garden are well worth the effort. You’ll:

• Reduce kitchen waste

• Improve soil structure and fertility

• Save money on fertilizers

• Contribute to a more sustainable lifestyle

Plus, there’s something deeply satisfying about turning something as small and fragile as an eggshell into lasting nourishment for your plants.