Can You Compost Eggshells? (Things You Should Never Compost)


Many people wonder whether they can compost eggshells, and if so, how effective they are at providing nutrients to plants.  I did some research on composting eggshells, along with some other common scrap materials, to find out more.

So, can you compost eggshells?  Yes, you can compost eggshells, but they will decompose faster when ground into fine powder.  Eggshells provide a good dose of calcium to soil, along with magnesium, potassium, and other trace minerals.  However, be careful about composting whole eggs, especially if they are rotten, since the smell can attract rats, raccoons, skunks, or other scavengers.

While I was learning more about composting eggshells, I found some other common questions that came up about composting.  For instance, can you compost banana peels, coffee grounds, bread, meat, dairy products, and paper towels?  How long do these materials take to decompose?  We’ll look at each of these questions in more detail below.

Can You Compost Eggshells?

Yes, you can compost eggshells.  However, be careful about composting whole eggs, especially if rotten, since they can attract rats, raccoons, skunks or other critters.

eggshells
You can compost egg shells, but they will break down faster if you grind them down small first.

When added to compost, eggshells provide the soil with a good dose of calcium (in the form of calcium carbonate), along with some magnesium and potassium.  All of these nutrients are essential to healthy plant growth. 

For more information, check out this article from Michigan State University on composting eggshells.

If you are worried about salmonella from eggs getting into your compost, be sure to use hot composting, rather than cold composting.  That way, the high temperatures will kill off any salmonella or other pathogens that may be present.

For more information on what materials to use for your pile, check out my article on composting.

One final note: the calcium in eggshells has a similar effect as the calcium in garden lime.  This means that it will make your soil less acidic over time, bringing the pH closer to 7.0 (neutral).  However, you might need lots of eggshells to achieve this effect!

How Long Do Eggshells Take To Break Down?

It depends on how finely ground or broken up they are.  When in small fragments, eggshells can take a year or more to break down.  When ground into fine powder, they will break down much faster, and be available to plants soon after applying to soil.

You can grind eggshells in a coffee grinder and mix the eggshell powder with water, and then apply it to your soil.  You can also put the powder in the hole when you transplant seedlings from indoors to the garden.

For more information, check out this article from the University of Illinois Extension on using eggshells in compost.

Can You Compost Banana Peels?

Yes, you can compost banana peels.  Banana peels will decompose to provide organic matter for your compost.

banana peel
Banana peels provide many important nutrients to a compost pile.

They will also provide nutrients, including potassium, calcium, iron, and manganese.  For more information, check out this article on the Research Gate website.

How Long Do Banana Peels Take To Decompose?

According to reference.com, it will take a banana peel three to four weeks to decompose most of the way in a compost pile.

Of course, this will vary depending on the activity levels of bacteria.  Their growth will be affected by the time of year, temperature, and humidity levels.  If you speed up the process, put your banana peel in a blender with some water and blend it up into mush.

Be sure to also include some “browns”, such as paper, cardboard, and straw, to go along with the “greens”, such as grass clippings, in your compost pile.  This balance will help the pile to turn into compost faster.

For more information, check out my article on making compost.

Can You Compost Coffee Grounds?

Yes, you can compost coffee grounds.  Coffee grounds will provide both nitrogen and organic material to your compost.

coffee grounds
Coffee grounds can provide some nitrogen to your compost pile.

For more information, check out this article from the Oregon State University Extension on composting coffee grounds.

Coffee grounds have a pH of around 6.5 to 6.8 (slightly acidic), so they won’t cause large fluctuations in the pH level of soil that is close to neutral.  In most cases, you won’t have to worry, since many plants prefer a pH in the range of 6.0 to 7.0.

How Long Do Coffee Grounds Take To Decompose?

Coffee grounds can take three months or more to fully decompose.  As with other materials, you can speed this up by using a good mix of green and brown materials in your compost pile, and also by keeping the pile moist (but not soggy).

For more information, check out this article from the University of California on composting coffee grounds.

Can You Compost Bread?

Yes, you can compost bread, pasta, and other foods made from wheat or other grains.  Much of the bread you buy at the store, including white bread, is fortified with calcium and iron, which are both essential nutrients for plant growth.

bread
Bread provides calcium and iron, along with other nutrients, to a compost pile.

Many types of bread also contain potassium, phosphorus, magnesium, zinc, and manganese.  By composting bread, you can add some of these nutrients back into the soil.

One caution is to avoid composting bread if you live near a restaurant.  You can attract nearby rats or other pests that are used to dining on bread from restaurants.

How Long Does Bread Take To Decompose?

Bread will decompose fairly quickly on its own without much treatment from you.  As everyone knows, bread without preservatives will be moldy in less than a week.

Even with preservatives, bread will grow mold within two weeks or so.  After mold appears, it will spread quickly and consume the entire loaf or slice of bread.

The same thing will happen in nature, and it will happen even faster in a compost pile.  If you want to speed up the process even further, soak the bread in water and then add it to your compost pile.

Can You Compost Meat?

Yes, you can compost meat, as well as fish.  However, the smell of composting meat will be revolting to anyone passing nearby, especially when the wind picks up.

meat
You can compost meat, but it probably isn’t a great idea, especially if you want to avoid pests like raccoons.

In addition, composting meat will attract flies, which will lay eggs.  Soon, you will have maggots squirming in your compost pile to feed on the meat.  This is not a charming scene to be setting in your yard.

As if that weren’t bad enough, you can attract feral dogs or cats, raccoons, and other scavengers that will be attracted by the smell of decomposing meat.  Once they learn that there is food to be had in your yard, they may come back for the produce from your garden.

For these reasons, it may be a good idea to throw away the meat instead of composting it.  If you do decide to compost meat, make sure to cook raw meat before putting it in your pile.  Otherwise, you will want to use hot composting to kill any traces of salmonella or other pathogens that may be present.

How Long Does Meat Take To Decompose?

Meat will probably be eaten by flies and scavengers before it gets decomposed by bacteria in your compost pile.  If you live near the woods, these scavengers will come quickly to make short work of whatever scraps you leave lying around.

Can You Compost Dairy Products?

Yes, you can compost dairy products, including yogurt and cheese.  They will provide a good dose of calcium to your compost pile.

cheese
Cheese can provide calcium to a compost pile, but it will smell terrible as it decomposes.

However, decomposing milk products will smell foul.  This smell is likely to attract flies and possibly larger pests to your compost pile.

For more information on what to do and what not to do, check out this article on composting from the Iowa State University Extension.

How Long Do Dairy Products Take To Decompose?

As with meat, dairy products will probably be consumed by flies and other pests before being completely broken down by the bacteria in your compost pile. 

Can You Compost Paper Towels?

Yes, you can compost paper towels.  Since paper towels are made from wood, they will break down in the same way that wood chips or branches would.

paper towel
Paper towels will decompose quickly in a compost pile, especially if wet.

However, since paper towels have been heavily processed, they will break down much faster than ordinary wood chips or branches.  If the paper towels get wet, they will decompose quickly in your compost pile.

One caution is that some paper towels are treated with chemicals in the production process.  If you are concerned about this, ask the manufacturer about chemicals used to treat the paper.

Cardboard is a close relative of paper towels, and you can use boxes in your compost pile, along with many other uses. For more information, check out my article on the uses of cardboard boxes in the garden.

How Long Do Paper Towels Take To Decompose?

Paper towels will decompose within a month of being placed in the compost pile.  You can speed this up by ripping the paper towels into smaller pieces and soaking them with water before placing them in the compost pile.

Conclusion

By now, you have a better idea of what types of things you can compost, and which ones you cannot (or should not!).  You also know how to speed up the composting process for many common food items.

I hope you found this article helpful – if so, please share it with someone who can use the information.  If you have any questions or advice about composting eggshells or other common materials, please leave a comment below.

jonathon.david.madore

Hi, I'm Jonathon. I’m the gardening guy (not guru!) who is encouraging everyone to spend more time in the garden. I try to help solve common gardening problems so that you can get the best harvest every year!

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