Eggshells are not waste

Author: Rachel  Date Posted:8 September 2020 

Eggshells are great for the garden, your veggies, pets and you! Eggshells are composed mostly of calcium carbonate, which is good for so many purposes! Find out how to make your own calcium supplement, pet supplement or plant food.


Eggshells are great for the garden, your veggies, pets and you!

Eggshells are full of calcium carbonate. They are not landfill. So, you’ve whipped up an omelette, baked a cake, made some quiches. What are you going to do with all those eggshells? In the bin?


Eggshells are composed mostly of calcium carbonate, which is good for so many purposes! The soil, vegies and plants, people and pets! At the very least, your crushed eggshells should go in the compost, or sprinkle your crushed eggshells in the garden or in your planters if you don’t have a compost.

Anything in your general waste goes to landfill, an anaerobic environment (with no air or living microbes to break down bio matter) where the waste creates biogas as it slowly degrades. This landfill biogas is around 40 – 60% methane, a greenhouse gas 25 times more potent than carbon dioxide. The remainder is mostly carbon dioxide.

But it's just one egg shell... said 7 Billion people.

According to Earth911, the US alone sends 150,000 tons of eggshells to landfills every year. That’s a lot of eggs! It's also a lot of greenhouse gas that can easily be avoided with so many more beneficial ways to use your eggshells.


Eggshells are full of calcium carbonate. They are not landfill.



You have to prepare eggshells? Well yes. But it's not hard!

Start by accumulating them in a container after use. Progressively, pop them in the oven (as you are heating it up or after cooking to reduce energy). This simply dries out the leftover egg white and sterilises them to avoid any contamination. Or as a batch, about 30 minutes at 100* Celsius should be enough to sterilise them. Don’t overdo it, as you don’t want to burn your eggshells. You can also leave them on a tray in the sun all day.

Once you have enough eggshells saved up and dried out, grind or crush them using a pestle and mortar, a coffee grinder or rolling pin. Eggshells do take some time to break down, so the more you grind them, the quicker they work. You will need various levels of grinding, depending on the intended purpose.



Eggshells are full of calcium carbonate. They are not landfill. Calcium from eggshells readily leaches into the soil. It moderates soil acidity and provides nutrients. Tomatoes, peppers and eggplants especially love eggshells.

Grind your eggshells to a fine powder to prepare soil for replanting. Use courser pieces for slow-release and create some drainage.

Worms love eggshells, too! Earthworms need grit to digest their food, and ground up eggshells are excellent for this. Use small pieces in your worm farm, or simply add them to your compost bin to help attract worms to your compost.

CALCIUM WATER: Another way to use your eggshells is by making calcium water for your indoor and outdoor plants and vegetable gardens. Simply steep your dried eggshells in water for a couple of days and use the strained water on your plants.

You could also bring the eggshells to a rolling boil for half an hour, and let the water cool before watering.

The left over eggshells from the calcium water can be crushed for mulch in the garden or to pop in the compost, or use finer pieces for the worm farm.

GARDEN COCKTAIL: For an extra garden booster, mix your crushed eggshells with used coffee grounds. Coffee grounds are rich in nitrogen, phosphorus and other minerals, making them a great natural slow-release fertiliser.



Humans need plenty of daily calcium, especially pregnant or breastfeeding women*. Dietary calcium increases the formation of both cartilage and bone in people with osteoporosis. It can significantly strengthen bones in post-menopausal women.

If we don’t get what we need, our bodies steal excess calcium stores from our teeth and bones. So instead of buying a manmade supplement that comes in plastic packaging, use wholefoods instead!

For your own calcium booster, steep sterilised eggshells with your coffee to have a calcium rich coffee. It will also temper the bitterness of the coffee and mellow out the flavour, which you may also enjoy more. You need 1 kilogram of broccoli to get the same calcium as in 1/2 teaspoon of powdered eggshells

You can also use it in fine powder form by adding it to your smoothies, juices or breakfast cereal. Be prepared for a gritty consistency, much like ground nuts. Use about 1/2 teaspoon of calcium powder for around 400-500 mg of calcium. Or you could eat a kilogram of brocolli, instead.

Ensure eggshells have been completely sterilised before using. Store in an air tight container away from heat.

*Pregnant and breastfeeding women should get independent medical advice before consuming any supplement.



DOGS: You can use eggshells as a calcium supplement for dogs. This is especially good if they don’t chew on bones. Calcium helps develop strong teeth and bones, and boosts muscle and heart health. Make sure you use it in powder form, and about half a teaspoon per day mixed with the meal. Less for smaller dogs.

BIRDS: To supplement bird food, crush eggshells into fine bits and mix with your favourite bird seed.



The shells from boiled eggs will not have the same nutrient level as raw eggshells. Shells from boiled eggs are best crushed and used for worm farms or compost bins or accumulated to make an organic mulch.

Make sure you use your cooled boiled egg water on the garden so your plants or vegetables get the benefits from the nutrients that have leached into the water.


Do you use eggshells for another purpose? Let us know in the comments below.


Comments (2)

Kitchen blender

By: on 7 December 2022
To sharpen the blades of a blender , use a few eggshells and water , then you can use it on your indoor plants so not to waste either the eggshells or water .

Informative post

By: on 23 September 2022
Amazing post, I will take supplement for

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