Egg shells for the garden

I save, dry, and grind my (free-range, non-gmo) egg shells, to use in my garden, and for a calcium supplement to add to the raw food I make for my dog. But, 30-some-odd hens lay a lot of eggs, and even using them as fast as I do... well, there's an abundance! Do you think this could be a small income source - say at a local flea, given the current fertilizer shortages? If so, should I sell by volume or weight? And, what would be a fair price? I'm in Central Missouri, for reference.

What's the soil like in your area? Acid or alkaline?

I put all of our eggshells (and bones, and mussel shells) through the indoor wood fire in stainless steel steam table pans, the same way I make small batches of biochar. When they come out they're super crumbly and the minerals are more bioavailable. I mix them into compost, spread on the garden, and add to chicken feed. Our soils are on the acidic side, so I'm always happy for more calcium sources and this is a great one.

The soil in the whole area is incredibly variable. Most of our land is just rocks and clay, so I've not even bothered to test it. I was thinking more for container gardening, which is what I've mostly been doing, so far. If I'd have to char them, like that, before selling them, then it won't happen. Our fireplace is an expensive, unusable disaster, and a completely different chapter, unto itself, John isn't going to want me adding them to the grill, when he's cooking (he uses wood chunks) and it's just not worth using up extra resources, to make a few pennies.

Carla, I feel you have a great idea for selling powdered eggshells as a garden additive.  great thinking.

For fun, I looked on eBay and this is what I found "Crushed Egg shell 8 oz organic for chicken & fertilizers / garden / Cascarillas".  The price for 8 oz is $5.00 plus $5.30 for Standard shipping.

When I looked below at "Similar Sponsored items" I saw lots of listings for eggshells.  Mostly for about $1.00 an ounce.

I wonder if making a post in the Flea Market forum would get some results.

Thanks, Anne! Not sure why it didn't occur to me to look there, lol! I'll go have a look. I don't think I want to ship, but that's still great info to have, in case I change my mind, later. I can easily package it in good ol' compostable brown paper lunch bags, too. Taking a stack of bags, a scoop, and a scale, along with a tub full of powdered shells would be easy to take in a basket. There's a little flea market with first- come-first-served-byo-booth plots, for $5 - $10/ day, depending on where you set up. John and I decided last summer that we would see what we could put together, and try our hands at it, this summer. It's across from the local Walmart, and it's set up next to the park district's baseball & soccer fields, so plenty of parking, which equals pretty decent traffic, for sales.

If I ever get enough stuff felted and wooden, maybe some of those things will sell, too.

The thought of shipping egg shells, which should be available in every community, freaks me out a bit!

You'd have to sell a fair bit to cover even a $5 or $10 booth, so until you know you have a market, I'd try word of mouth through any organizations you belong to. Are there any local garden clubs? Do you have enough spare composted goat-shit that you could consider do an "all-natural potted plant fertilizer"? I like the idea of drying comfrey as an addition to seed starting mix. Most commercial seed starting mixes are sterile dead things. My seeds do fine in what I give them, which is composted horse/duck shit with some coir, clay dirt, biochar and a bit of perlite added to lighten it. My seedlings get fed "real food" from the day they hatch (fine, germinate - I've got ducks on my mind...)

Seriously Carla: I was just wondering how I could get my hands on a cubic foot bag of white eggshells! Here's the reasoning.
Living here in the high desert, the sun is really intense and the climate can get extremely hot. To reduce the heat, save plants and conserve water, I am painting the hardscape around me (rocks, concrete pavers, stucco walls...) with a paint made of white clay, flour paste, and white sand. I'm also painting my fruit trees with repurposed white latex paint to prevent sun scald.
Then I thought about the soil itself: how can I make that dark soil reflect the grow light spectrum onto the plants rather than have the dark surface absorb the heat and fry the tender flora? What can I use to cover the dirt instead of white paint? What could replace all that plastic shade cloth?
So I switched from brown eggs to white just to have the albedo effect better cool my soil. An abundance of white shells to scatter around my seedlings would protect them from extreme heat, reflect the grow spectrum onto the plant, cool the soil, and perhaps even protect the new stems from certain pests. I'm doing a preliminary test to identify whether or not the sugar snap peas do better with the shells covering the surface.
I'm not sure how many ounces would cover 1 sq foot of garden space but I would buy crushed shells by the a cubic foot if they would improve the success of the garden. A cubic foot of eggshells would cover ~48 sq feet with 1/4" of white reflecting surface. It seems to me that using eggshells could be a fabulous approach to cooling, improving yields, and possibly other benefits.
Conducting tests with gardens that use the white shells and comparing their outcomes with black garden soil surfaces would help identify the real value of this product. Also, I have no idea how a 1/4" layer of eggshells woul change soil chemistry (maybe a question for a soil expert like Dr. Redhawk).
If you want to learn more about the amazing cooling power of white surfaces, watch this amazing segment from PBS:
https://www.pbs.org/video/the-whitest-paint-1634594293/
Good luck with your business venture Carla!

Nope. Too lazy, for that, lol. I've no intention of shipping. Too much like work, lol.

Amy, an anecdote from Eliot Coleman from one of his books, when he established his farm he tilled in oyster shells to adjust the pH of the former pine forest soil. Onlookers thought that was foolish, as it would take 30 years for the shells to break down... Coleman thought that was great, he wouldn't need to repeat this for 30 years!

Maybe something larger like crushed oyster shell might be slower to affect the pH than crushed eggshells with so much more surface area.
In coastal areas, there is an effort to return the shells to the sea to benefit the oyster beds. In your area, however, you might find a seafood dealer or restaurant that would give them away.

Carla, this might help in your estimating yields... I have saved our eggshells over this past year.  I don't recall my exact start date, but it was between mid-February and mid-March, so that's now-ish... We go through ~90 eggs per month, so 90 dozen, or 1080 eggs. I maybe missed a dozen or two, those went into the compost pail, so not "lost" just not set aside. It amounts to two, half-gallon paper milk cartons full, and weighs 10.25 pounds. The nested halves of eggshells make four neat stacks in the carton, and I keep smooshing them down as the stacks reach the top, until they won't smoosh anymore... I pulverized one carton, and was surprised to find that didn't reduce the volume by much at all.

Kenneth Elwell wrote:Carla, this might help in your estimating yields... I have saved our eggshells over this past year.  I don't recall my exact start date, but it was between mid-February and mid-March, so that's now-ish... We go through ~90 eggs per month, so 90 dozen, or 1080 eggs. I maybe missed a dozen or two, those went into the compost pail, so not "lost" just not set aside. It amounts to two, half-gallon paper milk cartons full, and weighs 10.25 pounds. The nested halves of eggshells make four neat stacks in the carton, and I keep smooshing them down as the stacks reach the top, until they won't smoosh anymore... I pulverized one carton, and was surprised to find that didn't reduce the volume by much at all.

Hi, Kenneth. I do it in stages. As I use them, I dehydrate them, then (like you) collect and crush them, as the container fills. But, I'm taking it a step further. My eggshells are not just crushed - I powder them. So, what fills a 2gal container, when crushed, becomes less than a 1 gallon container, after being ground down to a powder. This is why I'll weigh it, to sell - much more accurate, and if some turns out to be slightly more or less finely ground, I'll not accidentally short my customers or myself. I'm not really going to worry too much about cost/ profit analysis, because I'm already doing all the work, for my own use - so I already have the equipment and I'm already using the electricity. The only added things would be the bags, and an ounce or two in sales would more than cover a pack of 50 of those. The booth is something my husband is getting, anyway - which means I'll be out there, shells or no. This whole endeavor would be just a bit more pocket money for me and for the family till.

Carla, if you are removing all those eggshells from the nutrient cycle involving your chickens, are you feeding them calcium in some other form? I've heard you can feed rinsed crushed eggshells back to your chickens and it won't (usually?) lead to them pecking eggs.

I do, Rebecca. 😁😉 I mix some into oyster shells for them, and they have free access. My thought with mixing, instead of going with only their own shells, is to help offset any possible deficiencies being perpetuated. I try hard to cover all my bases.

Believe it or not, I live right by the ocean, and for over a year, all our local feed stores have been "out" of crushed oyster shell??? Go figure! I'm glad you guys can still get it, because I agree with Carla - I think magnesium is one of the things that may be higher in oyster shell than eggs shell and is good for chickens, but don't quote me on that since it's been a while.