32 Grenville Street M4Y 1A3



Christopher Greaves

Vermicomposting – Egg Shells

Monday, June 09, 2014

One of the most annoying myths I hear about vermicomposting is “Not only CAN egg shells be added to the vermicomposter, egg shells SHOULD be added to the vermicomposter”.

The myth-spinner commonly adds that “Worms love to eat egg shells, and they [the egg shells] disappear quickly”. Sometimes “Very Quickly”.

My limited knowledge of Red Wrigglers is that these worms carry no teeth; red wrigglers scrape the bacterial film off the surface of rotting food. They “gum” it off.

I cannot prove that red wrigglers don’t eat egg shells, nor can I prove that they do, but I can suggest that the myth might not be based on fact by setting up a little study to demonstrate that egg shells can disappear without the agency of worms.

This is not a scientific experiment; it neither proves not disproves a theory. And it is not falsifiable. It merely suggests an avenue of study and opens the door for someone to dispel the myth that Red Wrigglers eat egg shells.

I have amassed a quantity of dried egg shells. I have access to a variety of natural acidic compounds. I plan to put the two together to see if, and if so how quickly, natural acids in the vermicomposting bin might account for the disappearance of egg shells.

(1) I have a bag of egg shells harvested from a variety of situations and stored for varying periods.

(2) I have a set of washed, rinsed and dried milk bags made of clear plastic.

(3) I have an array of acidic fluids.

(4) I have the time to sit and observe progress.

I will grind (in my meat grinder) the dried egg shells and mix them well. The egg shells have been accumulated in my home and in the home of a friend. When I buy eggs I buy the cheapest available; when my friend buys them she tends to go for the latest trend – Omega-3 or Brown or Plastic Containers.

I cook at home and I cook at my friend’s place. Sometimes the eggs are broken open for frying and the half-shells left to dry out. Sometimes I make a soft-boiled egg, sometimes hard-boiled. In any event I save the shells.

The milk bags are harvested from my friend’s home; as each bag is emptied it is slit open at the end, washed in mild soapy water, rinsed twice and left to dry. I will re-rinse the bags at the start of this experiment.

My acidic fluids are summarized in the table below. I plan to use the fluids at supplied strength and diluted in water in two dilution ratios of 1:2 and 1:4. On a recent medical examination I learned that my urine sample contained no bacteria, so I have added bacteria-free urine to my list of acids.




Tap Water


Vinegar (Acetic Acid) 1:1


Vinegar (Acetic Acid) 1:2


Vinegar (Acetic Acid) 1:4


Vinegar (Acetic Acid) 1:4


Lemon Juice (Citric Acid) 1:1


Lemon Juice (Citric Acid) 1:2


Lemon Juice (Citric Acid) 1:4


Lemon Juice (Citric Acid) 1:4


Urine (Uric Acid) 1:1


Urine (Uric Acid) 1:2


Urine (Uric Acid) 1:4


Urine (Uric Acid) 1:4


Castings Tea (Tannic Acid?) 1:1


Castings Tea (Tannic Acid?) 1:2


Castings Tea (Tannic Acid?) 1:4


Castings Tea (Tannic Acid?) 1:4


Indian Tea (Tannic Acid?) 1:1


Indian Tea (Tannic Acid?) 1:2


Indian Tea (Tannic Acid?) 1:4


Indian Tea (Tannic Acid?) 1:4


Soil – damp


Castings - damp

To each bag I add a heaped tablespoon of ground dried egg shells then add the acid matrix.

The bags will be stored in an airy box in a dark place, to reduce the impact of stray sunlight on the mixture.

I will make no quantitative measurements (weight, proportion of shell remaining and so on) but will merely observe when the shells appear to have disappeared to my naked eye. It is, after all, the naked eye of the myth-spinners that is used to justify the claims that Red Wriggler Worms have eaten the egg shells.

You will note that in my table of acids I plan to use simply diluted solutions of acid, and am setting up TWO bags for the solution of 1:4. There is a simple reason for this.

The original solution might be a half-cup of (say) vinegar.

I then take another half-cup of vinegar, add a half-cup of tap water to make a 1:2 solution, and use a half-cup of this solution in a second bag.

I then take the remaining half-cup of 1:2 vinegar solution, add a second half-cup of tap water to make a 1:4 solution, and use a half-cup of this 1:4 solution in a third bag.

I am left with a half-cup of 1:4 solution and I can’t bear to just toss it down the drain! So I will set up a second 1:4 solution bag.

Saturday, August 23, 2014

Time to get started!

Christopher Greaves EggShells_HPIM7709.JPG

Here I am Grinding the dried egg shells into fragments of about four millimetre diameter. I’m using the coarse grinder plate and the grinder because I don’t want to spend a quarter-hour pounding away on the kitchen counter and sieving the results.

I have cut a milk-bag in half (SUFE) to channel the ground fragments away from the grinder. The elastic band (SUFE) once graced a book I had on hold from the Toronto Public Library. The bag of egg-shells is peeking in at the left-hand edge of the photo.

Christopher Greaves EggShells_HPIM7710.JPG

I use my large funnel – a cut-in-half milk jug (SUFE) to pour the ground fragments into a storage bottle.

Christopher Greaves EggShells_HPIM7711.JPG

Some of the shells display a clump of Mould or Bacteria. These will be shells that did not dry out quickly enough, but no matter; in the regular scheme of things we would be tossing un-dried shells into the vermicomposter, so the life forms would be there anyway.

Only if those fragments with mold have an effect on the particular vessel (out of the twenty-three established) would they sway my results. But I’m not conducting a scientific experiment here, so there’s nothing to falsify.

Christopher Greaves EggShells_HPIM7712.JPG

Here are some of the shells waiting to be ground; broken and nested as the day they were used.

Christopher Greaves EggShells_HPIM7713.JPG

And here is my harvest; about two litres of ground egg-shells – much more than I need for my first test, but a suitable reservoir in case I decide to conduct further tests.

I have shaken and tossed the jar around for fifteen seconds to further mix (randomize?) the contents.

Christopher Greaves EggShells_HPIM7725.JPG

And here I have twenty-three milk bags, numbered with a marker pen.

Each bag has a level desert-spoon of ground egg shell, and is now waiting for the appropriate solution.

Sunday, August 24, 2014

My delay in setting up the solution cells is caused in part by “other things in my life”, and by thoughts that strike me.

This morning I was going through some matrix from last week’s separation, obtaining rich soil to plant apple seeds and spider plant cuttings, and as I poked through the matrix with a plastic teaspoon I tossed worms into my Desktop Vermicomposter and observed small portions of egg shell. Those egg shells were tossed into the tower vermicomposter during the past year.

That the egg shells are still present suggests the possibility that the worms have NOT got around to eating them.

That the egg shells are still present suggests the possibility that the matrix is no longer acidic in nature.

I am currently drying and fine-sieving my wormless matrix to produce as homogenous matrix as possible.

It has not escaped my notice that where there are worms, there are worm eggs, so I shall try to separate them from my fine dry sieved material before using it in the cells.

Friday, August 29, 2014

Christopher Greaves EggShells_HPIM7753.JPG

Christopher Greaves EggShells_HPIM7754.JPG

Christopher Greaves EggShells_HPIM7755.JPG

Christopher Greaves EggShells_HPIM7756.JPG

Christopher Greaves EggShells_HPIM7757.JPG

Christopher Greaves EggShells_HPIM7758.JPG

Christopher Greaves EggShells_HPIM7759.JPG

Christopher Greaves EggShells_HPIM7760.JPG

Christopher Greaves EggShells_HPIM7761.JPG

Christopher Greaves EggShells_HPIM7762.JPG

Christopher Greaves EggShells_HPIM7771.JPG

Christopher Greaves EggShells_HPIM7773.JPG

Christopher Greaves EggShells_HPIM7774.JPG

Christopher Greaves EggShells_HPIM7775.JPG

Christopher Greaves EggShells_HPIM7776.JPG

Christopher Greaves EggShells_HPIM7777.JPG

Christopher Greaves EggShells_HPIM7778.JPG

Christopher Greaves EggShells_HPIM7779.JPG

Christopher Greaves EggShells_HPIM7780.JPG

Christopher Greaves EggShells_HPIM7781.JPG

Christopher Greaves EggShells_HPIM7763.JPG

Christopher Greaves EggShells_HPIM7764.JPG

Christopher Greaves EggShells_HPIM7765.JPG

Christopher Greaves EggShells_HPIM7766.JPG

Christopher Greaves EggShells_HPIM7767.JPG

Christopher Greaves EggShells_HPIM7768.JPG

Christopher Greaves EggShells_HPIM7769.JPG

Christopher Greaves EggShells_HPIM7770.JPG

Christopher Greaves EggShells_HPIM7772.JPG

Tuesday, September 02, 2014

So today (for another project) I was wading through some sieved material grabbing worms.

Christopher Greaves EggShells_HPIM7796.JPG

Here is a photo of the material spread out on a black plastic garbage bag. I have harvested the worms and am about to gather the bag by the corners and tip the examined material into another sack.

Christopher Greaves EggShells_HPIM7797.JPG

Then I realize that there is an abundance of egg shells in the matrix. The long white things are probably corn shoots from un-popped pop corn, or tomato seeds making a break for it. One or two of the irregular shapes might be pebbles.

A great proportion of the irregular shapes are fragments of egg-shells.

Christopher Greaves EggShells_HPIM7798.JPG

Here is more detail (above). Egg-shell, egg-shell, egg-shell, egg-shell, ...

Given that the food scraps (tea bags, coffee-grounds, orange peel, apple cores, banana skins etc) has been reduced to a micro level – I can’t spot any with my eyes – I can think of no better proof that Red Wrigglers do NOT eat egg shells than this residual accumulation of egg-shell fragments in the matrix long after the food scraps have been digested and the worms migrated elsewhere in search of Real Food.

Sunday, September 07, 2014

Nine or ten days have passed so I decided to check the bags of egg-shells.

Christopher Greaves EggShells_HPIM7828.JPG

Christopher Greaves EggShells_HPIM7829.JPG

Christopher Greaves EggShells_HPIM7830.JPG

Christopher Greaves EggShells_HPIM7831.JPG

Christopher Greaves EggShells_HPIM7832.JPG

Christopher Greaves EggShells_HPIM7833.JPG

Christopher Greaves EggShells_HPIM7834.JPG

Disaster is not the word!

(1) Some of the bags have leaked; the cardboard carton has leaked and some of the (leaked) bags are dried.

(2) Not one of the bags has measurable signs of degradation of the egg shells.

(3) The smell is something awful; not just with the stale urine, but even with stale lemon juice. Why am I surprised?

So I have been merciful to myself and tossed all bags (and the carton) into the garbage. Yes. Me. Tossing stuff into the garbage. Sometimes you do what you have to do.

I realise that a much better method of tracking what goes on would be to set up a set of bags with solution, and then ADD miniscule (about one gram) amounts of egg shell on a periodic basis – perhaps once a week – until the egg shells were NOT disolved.


416-993-4953 CPRGreaves@gmail.com

Toronto, Saturday, January 09, 2016 10:22 AM

Copyright © 1996-2016 Chris Greaves. All Rights Reserved.