Where there are eggs, there are eggshells. And depending on how many soft scrambles or vegetable-stuffed frittatas you enjoy each week, those eggshells can begin to add up. Tossing your kitchen scraps into the trash is easy, but there's no need to throw away a perfectly good source of calcium when there are gardens to grow and compost to be made. Read on to learn how to reduce your household food waste by composting eggshells at home.
Can eggshells be composted?
We'll set the record straight once and for all: leftover eggshells are a perfect addition to your compost bin. Not only are eggshells 100% biodegradable, they're a wonderful boost of calcium and other essential nutrients for your compost that support plant growth. Amending your compost and home garden with ground eggshells can reduce waste while offering your plants the calcium needed to build strong cell walls, fight off pests, and avoid common diseases like blossom end rot.
Are eggshells safe to handle?
If you've been following proper egg safety at home, the good news is that your risk of salmonella exposure from fresh organic eggs should be minimal. That said, handling freshly cracked eggshells does call for a few extra measures to reduce the risk of salmonella in your compost. After all, the last thing you want is a contaminated compost pile in your backyard. Rinsing and sterilizing your eggshells in the oven will kill salmonella and remove any pesky pathogens from your eggshells, rendering them safe and beneficial for your compost pile.
How long does it take for eggshells to decompose?
We hear this question often: "Won't eggshells take forever to decompose at home?" And the truth is, it depends! Whole eggshells and larger eggshell fragments could take up to a year or more to break down in your compost bin. Thankfully, there are options for speeding up the process.
Eggshells that are broken down into small pieces or a fine dust are much quicker to decompose, and come with the added benefit of immediately boosting the nutrient profile in your compost. Finely ground eggshells are also less likely to attract pests to your backyard, which is important if you live in a residential neighborhood or with young children. For best results, we suggest using an old coffee grinder or mortar and pestle to process your washed and dried eggshells before adding them to your compost bin.
How to compost eggshells
What you'll need
- 12-15 eggshells
- Paper towels
- Gallon-sized plastic bag (optional)
- Baking sheet
- Spice grinder or mortar and pestle
Composting your eggshells is easiest to tackle in batches, so gathering a hefty pile to process all at once is a good idea. Collect your used eggshells by rinsing each eggshell with water and placing on a paper towel in a single layer to dry. To save on counter space and avoid any unpleasant odors, you can also rinse and place your eggshells in a plastic bag inside the refrigerator or freezer for longer storage until you're ready to process.
Once you've collected a decent amount of eggshells (we prefer to aim for one gallon-sized plastic bag per batch), it's time to dry them thoroughly and neutralize any lingering risks of salmonella. Preheat your oven to 200F and spread the eggshells onto a baking sheet in a single layer. Bake the eggshells in the oven for 20 minutes, working in batches if necessary. Remove from the oven and let your eggshells cool for easier handling.
Farm Team Tip: Save time and conserve energy by waiting to bake your eggshells until the next time you need to preheat your oven. Once you're ready, simply place your baking sheet of eggshells in the oven while preheating for at least 20 minutes to dry completely and kill any unwanted bacteria.
Transfer your dried eggshells to a coffee grinder or mortar and pestle. Grind your eggshells down into a fine powder to allow for easier decomposition, working in batches as needed. This process can be rough on kitchen appliances, so we suggest using an older or well-used coffee grinder to avoid unnecessary wear and tear.
Once your eggshells resemble a fine powder, they're ready to be added to your compost bin or stored in an airtight container until needed. Apply ground eggshells to your compost by sprinkling overtop your compost pile, using a rake or shovel to mix and turn into your compost if desired.
Additional uses for eggshells
If your family goes through quite a few eggs or you end up with more ground eggshells than you know what to do with, there are plenty of uses for eggshell powder around the home and garden:
- Fertilize your houseplants in the spring by working a tablespoon of ground eggshells into the soil at the top of the pot.
- Keep grasshoppers and beetles out of your prized vegetable patch by sprinkling ground eggshells around your garden or at the base of each plant.
- Offer your backyard chickens a boost of calcium by adding a few tablespoons of ground eggshells to their feed.