Is Egg Shell Biodegradable?

Eggs are a key dietary component for most of the world’s population. Over 1 billion eggs are consumed every year around the world and this number continues to grow.

Eggs are a great source of nutrition, but are eggshells biodegradable, and if not, are they a cause of environmental harm? We find out in this article.

Are Eggshells Biodegradable?

Yes, eggshells are biodegradable.

Eggshell is made from calcium carbonate (CaCO3) crystals. It is a semipermeable membrane which allows air and moisture to pass through the shell. The shell also has a thin outer coating called the bloom or cuticle that helps keep bacteria and dirt out.

Given enough time, eggshells biodegrade while in the natural environment.

How Long Do Eggshells Take to Biodegrade?

The rate of decomposition depends on several environmental factors including soil conditions, animal activity and the climate.

Eggshells take in excess of 3 years to break down. In an eggshell decomposition study, the outer shell was found intact after a year underground.

The shell left in a container for the same duration didn’t show any signs of decay.

Eggshells decompose faster in moist conditions. Increased levels of acidity can also speed up this process.

Is Eggshell Recyclable?

No, eggshell isn’t recyclable.

There is no recognised recycling program for the processing of waste eggshells.

Eggshells either need to be disposed of in the garbage or added to a compost bin.

Is Egg Shell Good for Plants?

Yes, eggshells are beneficial to plants. Eggshells’ major component is calcium.

Calcium plays a vital role in plant growth as it helps them build strong cell walls, boosting their growth rate.  

Eggshells also improve soil structure.

This is why experts encourage gardeners to use eggshells when they’re preparing compost.

Why You Shouldn’t Put Eggshells in Your Garbage Disposal

The blades in your waste disposal unit will turn egg shells into a fine paste that might cause a blockage in your drainage system.

Place waste egg shells straight into the bin or your compost heap instead.

The Best Way to Reuse Eggshells

If you would rather not throw your eggshells into the bin, there are many things you can do to reuse them.

Here are several uses for your old eggshells:

  • Feed chickens. Crush eggshells and mix it with feed for your chickens.
  • Use eggshells in your garden to deter pests. They cut and kill pests such as snails, slugs and cutworms.
  • Organic gardening. Calcium in eggshells promotes increased growth for plants.
  • Decoration. You can make holes in or paint eggs for Easter and Christmas decorations.
  • Use them as seedling pots.


Eggshells are biodegradable and compostable but they cannot be recycled.

Feel free to place used eggshells into your composter or simply throw them away. Eggshells pose no harm to the environment.

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