Calcium Supplements for Your Garden

I love it when gardeners come over. I always learn something new about my space through their questions. And it’s usually the questions I answer “no” to that bring something to my attention that I didn’t think about before.

A friend recently came over, who’s pretty into fruit trees and nerded out with me over my espaliers and visions of a mini-orchard. Of course, when he asked me what I did to establish my trees, I had a very simple answer – not much. I know that it’s better to add compost as a mulch than in the beginning hole so that you encourage good root growth. I did that. I know that it’s good to plant bare root trees on top of a mound of soil with the roots spreading out and flowing down. I did that. I learned that it’s best for the tree to have good exposure to east facing sun so that the morning dew dries off quickly. I did that (not knowingly though). Growing fruit trees is still something I’m learning about. So then, he tells me that apple trees benefit from a little calcium since that’s what gives an apple its crunch! And who’s got five little natural calcium producers in her backyard coop? This girl! The egg shells! How I’ve been wasting this precious resource!

Ok, so they’ve been going into my compost, which eventually gets to my plants so it hasn’t been a total waste, but man, what potential they have! Did you know that besides putting them around your apple trees, they help out your tomatoes too?! Yep! The calcium boost helps prevent blossom end rot! Who knew?! Also, did you know that adding crushed egg shells is like adding lime to your soil, boosting the pH? I know! Oh, and you know, of course, about egg shells and their slug-deterring properties, right? Score!

I always remember my mom putting them around house plants too. It just took this one conversation, years later, to push me into action. That’s how things work sometimes. So here’s the deal. Stash a container near your compost bucket at the sink, designated especially for egg shells. Try and find a container with added ventilation, like a plastic berry basket. I knew I was holding on to that sucker for a reason!

Next, make sure to wash out the egg shells before you put them in your stash. We don’t want to create a fruit fly bonanza, right? Right. I’ve been collecting shells for a week and there was nary a fruit fly in sight!

Once you have a good pile, crush them to make them more accessible to your plants. I gave ’em a few pulses in the food processor, but alternatively, you could put them in a reusable bag and give them a smash, uh, I mean, gentle roll with a rolling pin. That way you’re not using added energy to create this supplement…except yours, of course.

Finally, sprinkle them around your plants and let nature take its course! Natural calcium supplements for your plants and “garbage” solution! If only I could get my calcium this way!

Maybe that means that you should come over so we can learn from each other too?


13 thoughts on “Calcium Supplements for Your Garden

  1. Katie

    This is great! I’m going to try this on my tomato plants, a couple of which have had blossom end rot this year. Thanks for passing this great info along!

  2. Kathleen

    I’ve been doing this for a year now just trying to prevent slugs. I love hearing all the other benefits. I wear a garden glove and just smoosh the egg shells. They are usually so brittle they they just crumble. In the spring I highly recommend saving all those colored egg shells from easter eggs and spreading them around. It adds some fun color when things are still kind of bare.

  3. Rebecca

    I was told to put the shells from a dozen eggs into the hole with each tomato plant I put into the ground in the spring. Although I don’t manage that many, I always start collecting shells around Easter for just that purpose.

  4. joel

    It will be years before the plant can use the egg shell’s calcium, you should use bone meal also. A soil test every 3-5 years would help, too.
    Keep adding the egg shells, they is far better in the garden/orchard then the land fill. You will need the proper levels of Magnesium or the plants can not use the calcium. Epson salt will do.
    Soil test is best to know how much of each of the17 elements are needed.
    If the temperature is over 90 degrees, then consistent watering will help move calcium into the root system of the plants. At or above 90 degrees inconsistent watering can cause BER. Some plants (tomatoes) are more likely to get BER not matter what you do.
    Because water consistent is import, one should mulch & water a little ever day or every other day. Sandy loam dry out faster then clay loam, so always check before watering.

  5. lynn

    yay eggshells! i don’t rinse mine and i haven’t had problems with fruit flies. they sit in a yogurt container on the counter. when one gets full in about a week, i start another. by the time the 2nd one gets full, the first one is dry enough for the ‘first crush’ which i usually just do with the 2nd container and then maybe a spatula. that is, if i get around to it. sometimes there might be a 3rd or 4th yogurt container going before i get to crushing. the only problem i had, and only once, was if i nested a bunch of egg shells wet…stinky, not good. i usually gently nest the two sides of one eggs shell but no more.

  6. Madeleine @ NZ Ecochick

    Great tip. Thanks heaps. I waill so being doing this my poor neglected apple tree. I’ve also been cleaning out my milk bottles with water and then pouring that water all over my tomatoes; leaves and all. I hear the calcium gets to them this way too and also the milk on the leaves “can/ might” help prevent blight. Here’s hoping!

  7. Shawn

    If you powdered your eggs you could get your calcium that way. Mix it in a smoothie, pancakes, or banana bread batter and instant calcium supplement. Wash them, and then bake them to get rid of any salmonella or other bacteria. Your pepper plants could use extra calcium and your hens too.

  8. Kitchen-Counter-Culture

    “If I could only get my own calcium supplement this way” — I’ve read (and done this) to throw egg shells in bone broth (with a little vinegar or lemon juice) or veg broth for calcium that can be assimilated.


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