Using eggshells in your garden

There’s a lot more to an egg shell than something that you’ve got to remove before getting to that delicious yolk inside. They’re complicated life support systems for the unborn chook and, even if unfertilized, still contain many compounds that can be good for you and your garden.

As we’re not poultry scientists, we’ll look at the basics and how we can use them in the garden.

What’s in eggshells?

Eggshell membrane mainly consists of protein in the form of collagen. It also contains small amounts of chondroitin sulfate, glucosamine and other nutrients. In addition to calcium and protein, eggshells also contain small amounts of other minerals, including strontium, fluoride, magnesium and selenium. 

Keep the inner membrane. Only remove it if you’re going to dry and store the eggshells. It’s food for microbes who will break down the eggshell in their own way, providing the best form and method of giving the compounds to your plants.

Calcium is probably the most important mineral for our purposes. Calcium helps to form the cell walls of plants and plenty of Calcium means strong walls which means that the plant is less prone to damage and insect attack.

Getting Calcium into your plants

There are three main ways to give your plants all of the Calcium they need –

Powdering eggshells and adding them to the soil

This is the easiest way to increase Calcium in your soil and potting mixes.

Simply crush the eggshells and dry them. Then put the dried shells into a blender and make a powder out of them. Then all you have to do is to sprinkle the powder and mix it in.

You don’t have too much, a teaspoonful is enough for a 50 litre pot. You just have to make sure that you mix it through your medium and that it doesn’t all end up in one place.

You’ll see folks recommending roasting the eggshells. That’s not necessary for this method but if you want to store the powdered shells or try any of the other methods listed below, it’s a good idea.

Roasting eggshells

Give the eggshells a rinse and put them into an oven at 170°C for 20 minutes. That’ll sterilise them a bit and burn off all of the organic material, leaving you with just the mineral components.

Water extraction

This is just like making eggshell tea! All you need to do is to boil some water and add some powdered eggshells to it. Let it boil for 20 mins or so, then let it cool overnight.

Strain off the water and repeat the process with any eggshells that are left. You can do this 2 or 3 times or until you get bored of the whole process. Any remaining shell can go into the worm farm or compost.

To use the results of the water extraction method, mix the cooled, filtered extract with rainwater at a rate of about 50 to 1 then use the mix as a root drench around your plants. The plants and soil organisms will do the rest for you.

Of course, you can just keep the water that you boiled your eggs in and after breakfast, when it has cooled, put it on yout plants. It won’t be very strong but it’ll have something in it.

Vinegar extraction

We have a whole page about vinegar extraction here LINK HERE

Other uses of eggshells

Chicken booster – powdered or at least finely crushed eggshells can be added to your chicken’s food toreplace many of the nutrients that went into making them. Another option is to add water or vinegar extract to their drinking water, especially if the vinegar used to make the extract is Apple Cider Vinegar.

Soil sweetener – the Calcium in the eggshells or either of the extracts helps to combat soil acidity by raising the pH. We say that it ‘sweetens’ the soil. Just sprinkle the powdered shells onto the soul or use water extracted calcium as noted above. Leave it two days before testing your pH again.

Slug deterrent – Using crushed eggshells is a traditional way of creating a barrier against Slugs and Snails. The sharp, jagged edges of the shell pieces deter the critters who don’t enjoy dragging their soft bodies over them. You don’t need to powder the eggshells for this, just dry them and crush them up by hand.

Using eggshells for yourself –

Eggshells have people uses too. You can drink the water or vinegar extractions, diluted to taste and they’ll add nutrients to your diet that are great for yoyrbones, teeth, skin and brains.

Another option is to add powdered eggshells as the rough component in home made hand or face scrubs.

A teaspoonful of powdered eggshells (mixed with a little water so that you can swallow it) makes for a reasonable antacid for when you’ve overdone things at the dinner table.