Skip to content

Eggshells for plants – how (and why) to use them

Did you know that you can use eggshells to feed your indoor plants? It’s true – and best of all, it’s free! Do you have a hungry plant in your collection, or a plant that’s looking sickly and you’re unsure what the problem is? Try using eggshells to make a nourishing plant fertilizer – I’ll tell you how below.

eggshells for plants

Don’t bin eggshells – feed them to your plants!

Most of us throw eggshells out without a second thought once we’ve enjoyed the contents. But hopefully I can persuade you to start saving them, because they’re crushable little powerhouses of plant nutrients.

Unlike outdoor plants, indoor pot plants can’t grow deep roots to seek out more minerals. Supplementing them with extra nutrients can help prevent deficiencies – which is where those shells come in…

fried egg with eggshells
Eggs for you, eggshell fertilizer for your plants

Eggshells are incredibly rich in calcium. They’re composed of about 95% calcium carbonate – the stuff our bones and teeth are made from.

Though not the tastiest snack, eggshells are actually edible. So if you fancy a crunch, half a shell will provide your daily recommended intake of calcium!

Why eggshell calcium is good for plants

Plants need a balanced diet of nutrients to stay healthy – nitrogen, potassium and phosphorus are the most important ‘primary nutrients’.

But smaller amounts of secondary nutrients are vital for plant health too. Calcium is one, along with magnesium and sulphur (both of which are also found in small amounts in eggshells).

healthy tomato plant close up

Besides enzyme activity and metabolism, calcium is needed to build strong cell walls. A lack of it can weaken plant cells and leave them vulnerable to pathogens. And this can lead to all manner of nasty ailments.

Leaf edge necrosis, leaf curl, tip burn, root disease, stunted or deformed growth, blossom end rot – all can be caused by calcium deficiency.

Feeding your plants with calcium-rich eggshells can keep them fighting fit, help stave off diseases and encourage healthy growth.

How to make eggshell plant fertilizer

There are a few ways you can use eggshells for plants, so you can experiment and see which way works best. It won’t cost you a penny after all, so you’ve nothing to lose.

TOP TIP – If you’re trying more than one method, remember to keep a note of your results so you know which way was most effective for future reference.

The simplest way to make your plant feed is to crush the eggshells into a fine powder and apply or mix them into soil.

But you can also use eggshells to make a liquid fertilizer, using either water or vinegar as the base. The vinegar way is slightly more involved than water, but both are simple enough.

Using powdered eggshells for your plants

hammer crushing egg shell
Probably not the best way to crack an egg

To make a powdered feed, first you’ll want to give the eggshells a good wash inside with warm water.

There’ll be protein residues in there which may get a little whiffy in time, as well as encouraging pests.

Leave the clean eggshells to dry completely overnight.

Next morning, put the eggshells into a regular food processor, blender or coffee grinder. Crush them until you’re left with a coarse powder.

This powdered feed can then be sprinkled around the base of your plant on top of the soil. It will be absorbed into the soil when you water.

Alternatively, if newly planting or repotting, mix the powder into your potting compost. Make sure you give it a good stir to combine it well, and use around 5 powdered eggshells per plant.

Making eggshell tea liquid plant fertilizer

A different way, which is almost as simple, is to soak eggshells in water to make a sprayable or pourable liquid houseplant fertilizer.

eggshell tea liquid plant fertiliser spray

Just boil up a couple of pints of water, take it off the heat and add in 5 washed eggshells.

Crunch them into pieces first to increase their surface area and help leach more calcium into the water.

Leave the water to steep overnight, strain out the eggshells the next morning and use in place of regular water.

If you’re pushed for time, there is an even easier approach (though the nutrient content won’t be quite as high). Simply use the leftover water after boiling eggs.

If you’re used to having boiled eggs for breakfast, you can easily get into the routine of not throwing away your water.

It goes without saying, but make sure you leave it to cool to room temperature before watering your plants. They won’t thank you for soaking them with boiling water!

Eggshell and vinegar plant fertilizer

For those of you with an interest in chemistry, you might like this as there’s an actual chemical reaction involved. It’s also quite a fun one to try with kids.

Using cleaned and ground eggshells (prepared as above), mix one tablespoon of the powder with one tablespoon of white vinegar and leave overnight.

The acetic acid in the vinegar will react with calcium carbonate in the eggshells, visibly foaming and freeing up water-soluble calcium (calcium acetate).

The mix is too concentrated to use by itself, so dilute it with a gallon (8 pints) of water and give plants a good soak. The free calcium will be readily absorbed by plants’ roots from the wet soil.

Which plants benefit most from eggshells?

Any plant you’re growing indoors should benefit from the extra calcium in eggshell feed. But it will be particularly appreciated by edible plants, which are generally hungrier for nutrients than regular perennial houseplants.

Tomatoes especially, with their tendency to succumb to blossom end rot, are an ideal choice to supplement with eggshells.

And you may find indoor-grown carrots and lettuce leaves are happier with a regular feed of eggshell tea or powder too.

Over to you – never shell out on expensive plant fertilizers again

Whichever way you choose, eggshells are well worth trying as a fertilizer for indoor plants.

100% natural, readily available and packed with calcium, there’s also some protein and other trace minerals in there too. All of which helps ensure plants are getting everything they need.

Best of all, they’re FREE and let you make great use of waste that would otherwise be thrown away. What’s not to love?

Even if you have a go and don’t see much difference, you’ve lost nothing. So next time you make an omelette to feed yourself, you might want to save those eggshells to feed your plants too.

As ever, I’m always keen to hear your feedback on here. Have you tried using eggshells for plants with fantastic results? How about middling results? Or even distinctly unimpressive results? Let me know in the comments!

egg shell flower


  1. jim sterrett jim sterrett

    Some guys are trying to tell me that you MUST use vinegar to extract the calcium because the plants won’t absorb it if you dont

  2. Nangula Heita Mwampamba Nangula Heita Mwampamba

    Hi Kerry, thank you for the explanation around the use of vinegar. Could one use lemon or lime instead? I was thinking that instead of throwing out either eggshell or lemon/lime after squeezing out the juice, both “waste” materials could be soaked together in water to make the water soluble calcium available?

    • Kerry Kerry

      Hi Nangula, that’s a great question – thanks. I know you can dissolve eggshells in lemon juice to make water-soluble calcium citrate, so in theory your idea should work! I would try and extract any remaining juice you can from the spent lemons/limes, shred the peels up and add them, and top up with just enough water to cover the eggshells so you keep the acid as concentrate as possible while the eggshells are dissolving. Then dilute as normal and use as a liquid feed or foliar spray.

  3. Janet Janet

    How much is five eggshells worth of powderized eggshell? I’ve already processed a large amount and am ready to plant!

    • Kerry Kerry

      Hi Janet – good question! One eggshell typically makes about one teaspoon of powder – so 5 teaspoons 🙂

Leave a Reply