Can You Compost Egg Shells?
Cage-free eggs are an important source of protein, fats, and carbohydrates. They also contain other important vitamins and minerals. Therefore, for many people, eggs are an all-in-one nutritional package.
But what about the eggshells? Are those nutritional also? Should you throw them away or can you add them to the compost?
The short answer is yes, you can compost eggshells.
However, there is a longer, more nuanced answer about the details of composting eggshells. In this article, I will discuss not only the best way to compost eggshells but also the reasons why adding eggshells to your compost pile or garden beds can be advantageous. Keep reading if you're tired of throwing away eggshells and want to put them back to work after making eggs for breakfast.
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Do Eggs Break Down in Compost?
Yes, eggshells break down in the compost. However, the rate at which they do so depends on the size of the eggshell particulate.
The larger the eggshell fragments, the longer it will take for them to break down.
Ground or pulverized egg particulates will break down faster.
Over time, egg shells add calcium and other micronutrients to the soil.
Egg shells can also be helpful for aerating soil, preventing pests, amending soil, and supplementing the diets of egg-laying chickens.
What Are the Benefits of Composting Egg Shells?
Eggshells can be an important source of calcium and other essential nutrients for the soil and nearby plants. For example, magnesium in the eggshells helps aid the photosynthesis process, and potassium can help reduce wilting and water loss.
Like the composting process, in general, composting eggshells also help reduce the amount of excess kitchen waste you have at home. This inevitably helps reduce the amount of food waste that gets thrown into landfills.
Adding eggshells to your garden can also help increase soil aeration and drainage. This is particularly helpful in denser, clay-like soil types. Similarly, eggshells can help drop the acidity in the soil, which can be helpful for growing plants in a less acidic environment.
Composting Egg Shells: Step-by-Step Guide
There is a lot of information out there about how to compost eggshells. I’ve done my best to compile the most helpful stuff. Here’s what I’ve learned.
How Do You Prepare Egg Shells for Compost?
You should prepare your eggshells before adding them to the compost. Contrary to popular belief, you should not just throw the shells in the compost without preparing them beforehand.
You can prepare eggshells for the compost in three ways.
Baking
Boiling
Grinding
Baking your eggshells in the oven is one way to dry them out and prepare them for the compost. Drier eggshells are more amendable to being ground later on. However, depending on who you talk to, baking eggshells before composting is unnecessary.
Boiling eggshells in water is another way to prepare them for the compost pile or the garden. By boiling the eggshells, you create a calcium solution. You can then strain out the eggshells and amend your soil with only the solution.
A single eggshell adds four milligrams of calcium to the solution. Depending on the plant and your preferences, two cups of boiled solution per plant is adequate. You can apply the calcium solution every two weeks.
Grinding eggshells is another way to prepare them for compost. For most gardeners, farmers, and homesteaders, this is the preferred method. It’s quick and easy for you and easily “digestible” for the soil.
Do You Have to Rinse Egg Shells Before Composting?
Rinsing your eggshells before adding them to the compost is not necessary. But if it gives you peace of mind, go for it. Some people get peace of mind from rinsing their eggs before the compost because they believe it mitigates the risk of spreading salmonella from the eggshells into the soil and onto the food they are growing.
However, the reality is that spreading foodborne pathogens like salmonella through the soil is highly unlikely, especially compared to coming into contact with raw eggs in the kitchen.
Yes, all sorts of bacteria exist in the soil, however with proper hand washing and food preparation practices you mitigate the affect these bacteria coil have on your health. Similarly, hot composting will all but eliminate the likelihood of this or other microbes from getting their way into your food.
Should I Crush My Egg Shells Before Composting?
Yes, it’s better to crush or pulverize your eggshells before adding them to the compost.
If you simply chuck your eggshells directly in the garden or compost pile without grinding or pulverizing the shells, they will take ages to break down in the garden. This can be somewhat unsightly, and it doesn’t help out the soil.
Therefore, in order for your eggshells to have the largest impact, you need to help them out by grinding them first. The easiest way to do this is with a kitchen coffee or spice grinder. When using a grinder, mortar and pestle, or food processor to grind your eggshells, the finer or more pulverized you can make the eggs, the better.
How Many Eggshells Should I Compost?
Eggshells take a lot longer to break down than other foods in the compost pile. Therefore, it’s easy to end up with a lot of shells, especially if you consume eggs on a daily basis. Fortunately, you are not harming your compost pile by adding a lot of eggshells.
For those who are asking, “How many eggshells is too many?” well, there’s no hard and fast number of crushed eggshells that you can compost at one time.
However, it is helpful to understand that eggshells tend to increase the acidity of the compost. This isn't a problem per se, but it's something to consider, especially if you plan to use the compost for plants that thrive with low pH soil.
How to Prevent Egg Shells in Compost from Attracting Pests
If you eat a lot of eggs and like to add them to your garden beds or compost pile, it’s possible that the shells will attract pests, like curious rodents and skunks looking for food. This is especially true if you have not prepared the eggshells beforehand.
Preparing eggshells beforehand by grinding them into a fine powder is the most effective way to compost eggshells while avoiding attracting pests. This will also make the shells more easily absorbable by the soil.
However, to be honest, it’s not that big of a deal. Rodents and vermin are not too overly curious about empty eggshells.
How Long Does it Take Egg Shells to Break Down in the Compost?
The length of time it takes for eggshells to break down in the compost depends on the size of the eggshells. The larger the eggshell particulate, the longer it will take to break down.
For example, freshly cracked eggs that have not been prepared or ground in any way beforehand can take years to break down completely. One gardener found that the eggshells they used were largely unaffected after five years.
On the other hand, the smaller or finer the eggshell particulate, the faster it will break down in your soil. Finely ground eggshells can break down in your soil within a matter of weeks or months.
Other Ways to Use Egg Shells in the Garden
Egg shells make for a great compost additive. However, there are some other creative ways to use eggshells in the garden besides enriching your compost.
Pest control: The sharp edges of eggshells can help deter certain insect pests like slugs and snails. As a pest deterrent, the larger the egg shells, the better. However, they will break down slower.
Chicken feed: Ground eggshells can actually be supplemented back into your chicken’s feed to help enrich their diet with more calcium. This can be especially helpful for egg-laying hens who are producing a lot of eggs.
Soil additive: You can amend your soil with eggshells to create a less acidic soil composition. Amending your soil to become less acidic can help certain plants grow that may be struggling with soil that is too acidic.
Mulch: Larger or chunkier unprocessed egg shells can easily be added to a mulch mix for mulching around trees, rose bushes, or other plants that thrive with mulch.
What Else Can You Compost?
In general, compost ingredients can be broken down into two categories: greens and browns.
Greens are nitrogen-rich materials, including grass clippings, fruit and vegetable scraps, coffee grounds, tea bags (without the staple), and, of course, eggshells. Any kind of food scraps are generally a good candidate for the compost heap.
Browns are carbon-rich materials. Examples include plant twigs and stalks, dried leaves, untreated wood chips, shredded cardboard (no wax coating and no glue), shredded paper (non-glossy and uncolored), and shredded brown bags.
Materials to Avoid Adding to the Compost
Not everything should be added to your compost pile. Some materials, like meat, fish, and bones, can attract nuisance animals. In addition, most backyard composting operations do not reach high enough temperatures to break down materials like compostable food service ware and compostable bags
Meat, fish, and bones
Cheese and dairy products
Fats, oils, and grease
Cooked food (small amounts are fine)
Compostable food service ware and compostable bags
Herbicide-treated plants and grass
Aggressive weeds/weeds with seeds
Diseased and pest-infested plants
Treated or painted wood
Pet waste and cat litter
Dryer lint
Glossy paper
Produce stickers
Final Thoughts
If you enjoy eggs and you like composting, then absolutely add your eggshells to your compost! Eggshells can serve as a valuable source of calcium and other helpful vitamins and minerals for your soil and plants.
Plus, composting eggshells can reduce the amount of kitchen waste you throw out. Eggshells can also be used as mulch, to amend overly acidic soils in raised garden beds, to deter certain pests, and as a nutritional supplement for your chicken flock.
Just remember, eggs take time to break down. This isn’t a big problem, but if you don’t like the look of eggshells in the yard or even your finished compost, grind them into a fine powder. Ground eggshells are also more readily absorbed by the soil.
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