what's in an eggshell?

[wyverne]

I usually just throw eggshells onto the compost heap, but I can't help thinking they've got more specific uses than that. Can anyone give me an analysis of the minerals etc in eggshells - from free-range hens of course!
wyverne

[Jess]

Hi and welcome to the forum.
They are used to 'sweeten' the compost. Main component being calcium carbonate. This means eggshells stop the compost becoming too acidic which could harm your plants.
There are also small amounts of phosphorous and magnesium.

[doccat5]

And worms love em with a little newspaper and coffee grounds on the side

[opabinia51]

Little known fact, eggshells also contain both Macronutrients NPK and micronutrients other than Ca. They are very high in Nitrogen as well and are actually considered a green as far as compostables are concerned.

They are great for growing tomatoes because the calcium helps stem blossom end rot. So, sprinkle them around your tomatoe plants.

[cynthia_h]

https://ps.fass.org/cgi/reprint/79/12/1833.pdf is a detailed scientific study re. the composition of eggshells.

Not sure whether you're interested in this level of detail, but I'm sure that absolutely everything is in this article (at least, re. mineral constituents ).

Cynthia H.
USDA Zone 9, Sunset Zone 17

[Jess]

Here is the complete list of what constitutes an eggshell complete with some adhering albumin.....

Water, % 29-35
Protein, % 1.4-4
Crude Fat, % 0.10-0.20
Ash, % 89.9-91.1
Calcium, % 35.1-36.4
CaCO3, % of total Ca 90.9
Phosphorus, % 0.12
Sodium, % 0.15-0.17
Magnesium, % 0.37-0.40
Potassium, % 0.10-0.13
Sulphur, % 0.09-0.19
Alanine, % 0.45
Arginine, % 0.56-0.57
Aspartic Acid, % 0.83-0.87
Cystine, % 0.37-0.41
Glutamic Acid, % 1.22-1.26
Glycine, % 0.48-0.51
Histidine, % 0.25-0.30
Isoleucine, % 0.34
Leucine, % 0.57
Lysine, % 0.37
Methionine, % 0.28-0.29
Phenylalanine, % 0.38-0.46
Proline, % 0.54-0.62
Serine, % 0.64-0.65
Threonine, % 0.45-0.47
Tyrosine, % 0.25-0.26
Valine, % 0.54-0.55

[TheLorax]

Neat thread. Lots of good information.

I don't know why your link didn't work but here it is again-
https://ps.fass.org/cgi/reprint/79/12/1833.pdf

[Niesha]

I also heard that eggshells are good to mulch with to keep the snails and slugs away. Does anyone know if this is true?

[minnesota_girl]

Anything sharp, the way I heard it they cut themselves on the eggshells but I've never tried it.

[TheLorax]

I also heard that eggshells are good to mulch with to keep the snails and slugs away.

Could be one of those urban legend type deals. It never worked for me.

[koonaone]

Clearly they contain eggs.

douglas

Hah! Peak oil? Try Peak water, and Peak Land at the same time. Overgrazed is more like it.
https://www.alternet.org/water/93170/?page=entire