How to Compost Eggshells: A Guide to Sustainable Gardening

Composting is a fantastic way to reduce waste and create nutrient-rich soil for your garden. While many people are familiar with composting kitchen scraps like fruit and vegetable peels, eggshells are often overlooked.

However, eggshells can be a valuable addition to your compost pile, providing essential nutrients and helping to balance the pH levels of your compost. In this article, we will guide you through the process of composting eggshells, allowing you to maximize the benefits of your composting efforts.

Why Compost Eggshells?

Eggshells are composed primarily of calcium carbonate, which is an essential nutrient for plant growth. By composting eggshells, you can introduce calcium into your compost, enriching the soil and promoting healthy plant development. Additionally, eggshells can help to balance the pH levels of your compost, creating an optimal environment for beneficial microbes to thrive.

Preparing Eggshells for Composting

Before adding eggshells to your compost pile, it’s important to prepare them properly. Follow these steps to ensure the shells break down effectively:

  • Rinse the shells: After using eggs, rinse the shells under cool water to remove any residual egg white. This step helps prevent odors and the attraction of pests.
  • Dry the shells: Allow the rinsed shells to air dry completely. Placing them on a drying rack or in a sunny spot for a day or two should be sufficient. Drying the shells reduces their moisture content, enabling them to break down more easily during the composting process.
  • Crush the shells: Once dry, crush the eggshells into small pieces. You can use a mortar and pestle, a rolling pin, or simply crush them with your hands. Breaking them into smaller fragments increases their surface area, making it easier for them to decompose.

Adding Eggshells to Your Compost Pile

Now that you have prepared your eggshells, it’s time to incorporate them into your compost pile. Follow these guidelines for optimal results:

  • Layering: When adding eggshells to your compost pile, it’s best to layer them with other organic materials. Alternate between dry, carbon-rich materials like leaves or straw, and moist, nitrogen-rich materials like kitchen scraps or grass clippings. This layering promotes proper decomposition and prevents the compost from becoming too compacted.
  • Balance the pH: Eggshells have a neutral pH, which can help to balance the acidity of other compost ingredients. If your compost is overly acidic, the addition of eggshells can help raise the pH and create a more favorable environment for beneficial microbes.
  • Avoid clumping: To prevent eggshells from clumping together in the compost pile, it’s essential to crush them into small pieces. This allows for even distribution throughout the pile and encourages quicker decomposition.
  • Composting method: You can choose from various composting methods, including traditional compost bins, vermiculture (using worms), or compost tumblers. Regardless of the method you select, the basic principles of composting still apply. Ensure a good balance of carbon and nitrogen, maintain moisture levels, and turn the compost regularly to aerate it and promote decomposition.

Additional Tips for Successful Composting

Here are some extra tips to help you achieve successful composting with eggshells:

  • Avoid adding too many eggshells at once, as this can disrupt the balance of your compost pile. Gradually incorporate them over time.
  • Consider crushing the eggshells into a fine powder using a blender or food processor. This speeds up decomposition and allows for easier absorption by plants.
  • If you don’t have an outdoor compost pile, you can still compost eggshells in an indoor composting system like a worm bin. Red wiggler worms are particularly efficient at breaking down eggshells and other organic matter, producing nutrient-rich worm castings that make excellent fertilizer for plants.
  • Remember to maintain a proper balance of green and brown materials in your compost pile. Green materials, such as kitchen scraps and fresh grass clippings, provide nitrogen, while brown materials, like dried leaves and twigs, provide carbon. Aim for a ratio of roughly 3 parts brown to 1 part green to ensure proper decomposition.
  • Keep your compost pile moist but not waterlogged. Eggshells, being primarily made of calcium carbonate, are porous and can absorb excess moisture, potentially leading to a soggy compost pile. Monitor the moisture levels and adjust as needed by adding water or dry materials.
  • Patience is key when composting. Eggshells, like other organic matter, take time to decompose fully. It can take several months for eggshells to break down completely into nutrient-rich compost. Be patient and continue to turn and aerate your compost pile regularly to speed up the decomposition process.
  • Utilize crushed eggshells in your garden directly. In addition to composting, you can sprinkle crushed eggshells around your plants as a natural pest deterrent. The sharp edges of the crushed shells deter slugs, snails, and other soft-bodied pests from reaching your plants.
  • Consider saving and sterilizing your eggshells before composting. By boiling the shells for a few minutes, you can eliminate any potential pathogens, making them safe to use in your compost pile or directly in the garden.


In conclusion, composting eggshells is a simple and effective way to maximize the benefits of your composting efforts.

By following the steps outlined in this guide, you can ensure that your eggshells break down efficiently, providing essential nutrients and balancing the pH levels of your compost.

Whether you have an outdoor compost pile or an indoor worm bin, eggshells can play a valuable role in creating nutrient-rich soil for your garden. So start saving those eggshells and contribute to a more sustainable and thriving garden ecosystem through composting.

Read more helpful article: Make a Compost Bin from an Old Storage Tub

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