Eggshell WCA (Water-Soluble Calcium)

Info Requested By - @meangreengrowinmachine

If you have been growing cannabis for very long then you know by now that every problem can be solved by adding Cal/Mag. While in reality Cal/Mag may not solve every issue it is still a very impotent component for the plants to build strong cell walls.

How much money do you spend a year on Cal/Mag?

Well, grab a stress ball because I'm about to show you how to make a shelf-stable Cal/Mag concentrate for around $20 that when added to water with a dash of Epson salt will yield 1000 Gallons of cal/mag solution.

What Is WCA?
Water-soluble calcium is a source of available calcium that can be made from commonly used household items, eggshells, and vinegar. When applied as a foliar spray, WCA provides available calcium to plants for normal cell processes, root growth, and fruiting (Hasenstein and Evans 1988, Marschner 1995, Hodges 2010).

I toss my eggshells in the freezer and once I have 50 or so I make a batch of WCA. 50 large eggs yield around 1 cup of cooked shells and are enough to make 10+ cups of WCA.


I like to use a cast-iron skillet on my electric burner so I can control the heat. I set the dial to 4 and set a timer for 60 minutes.


After 25 minutes


After 40 minutes


After 60 minutes


After they cool we will take them outside and toss them around (Flip them in the skillet) to remove the membrane inside the shell. Toss them gently or stir and fan them with a piece of cardboard and the membrane will fly out the pain leaving mostly eggshells. Any organic material will lessen the shelf life of your WCA

Now measure out 1 cup of shells and put them in a one-gallon glass jar and add 10 cups of vinegar.


Add the vinegar a few cups at a time to ensure the reaction doesn't cause the mix to overflow. You will instantly see bubbles start moving the eggshells around shooting them towards the surface and falling again. If this doesn't happen then you have not cooked your eggshells long enough.





I put my cap on loosely so the gas can escape. and in a few days when it settles down will use the vapor lock built into my lid but you can cover it with a paper towel or breathable cloth for storage until the process is done. We will wait 10 days for all eh calcium to be released from the eggshells before continuing.

Had someone make a comment on another forum questioning the effectiveness of WCA.
"How can this solution use such a small amount in comparison to what I buy from the hydro shop. So you think you can make a stronger solution than the scientist they hire. ROTFL This is bro-science shit"

My solution is still bubbling but let's put the tester in and see what type of TDS PPM increase we got in comparison to just straight rice wine vinegar.

Straight Vinegar comes in at a reading of 736 PPM TDS


WCA on day 8 comes in at a reading of 5460 PPM TDS

The X10 is just out of the photo

Now there is no way for me to tell what nutrients & minerals dissolved in this solution but it is my understanding that the majority of this is calcium. This is why we do our best in the cooking stage to remove all the organic material so that the toasted eggshell is all that remains.

I will do a final reading when the solution is finished and will grab some Cal/Mag solution and test it to compare the concentration of each.

The solution has stopped bubbling


I will use a coffee filter to remove all the small particles


Ready to roll and TDS is 5770 PPM


WCA is commonly diluted with water (1:1,000 ratio) and applied as a foliar spray (see Table 1) to flowering and fruiting plants (including vegetables). The best times to spray are just after sundown or very early in the morning, to prevent leaf burn and to allow sufficient time for absorption before evaporation from the leaf surface. Use a light mist; do not spray so heavily that the solution drips from the foliage (run-off). Plants require adequate levels of calcium to support fruit yield and quality and to prevent blossom-end rot. WCA is used in combination with other Natural Farming inputs including oriental herbal nutrient (OHN), fermented plant juice (FPJ), brown rice vinegar, and fish amino acid (FAA) as a seed-soaking solution prior to planting to improve seed germination and seedling vigor.

J.James said:

The solution has stopped bubbling


I will use a coffee filter to remove all the small particles


Ready to roll and TDS is 5770 PPM


WCA is commonly diluted with water (1:1,000 ratio) and applied as a foliar spray (see Table 1) to flowering and fruiting plants (including vegetables). The best times to spray are just after sundown or very early in the morning, to prevent leaf burn and to allow sufficient time for absorption before evaporation from the leaf surface. Use a light mist; do not spray so heavily that the solution drips from the foliage (run-off). Plants require adequate levels of calcium to support fruit yield and quality and to prevent blossom-end rot. WCA is used in combination with other Natural Farming inputs including oriental herbal nutrient (OHN), fermented plant juice (FPJ), brown rice vinegar, and fish amino acid (FAA) as a seed-soaking solution prior to planting to improve seed germination and seedling vigor.

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Thanks man! I have tons of eggs shells to use!

I like your process. I used eggshells that I boiled on the stove in plain water before but it wasn't good for my plants. Much too strong a solution I'm thinking from reading your post. Thanks!

While we are on the subject of replacing bottles with your own stuff. What are your thoughts on using a citric acid and water solution as PH down? Ok for the herd?

meangreengrowinmachine said:

While we are on the subject of replacing bottles with your own stuff. What are your thoughts on using a citric acid and water solution as PH down? Ok for the herd?

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If you have to PH adjust it, you shouldn't use it. That is my stance on the subject. This is the herds job, Feed them and they feed your plants

J.James said:

If you have to PH adjust it, you shouldn't use it. That is my stance on the subject. This is the herds job, Feed them and they feed your plants

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My water comes out of my well at like 9 ph and I use sips so there are water roots. I dont think putting 9 ph water in there would be a great idea.

meangreengrowinmachine said:

My water comes out of my well at like 9 pHs and I use sips so there are water roots. I don't think putting 9 ph water in there would be a great idea.

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This is true, now that I understand that your source water is the issue let me do a little digging in my notes and see what the guys over at buildasoil recommend on the subject.

Lemon juice or vinegar is what they recommend so that falls in line with your original citric acid comment. This WCA might be exactly what you need to balance everything out and add the Calcium you need at the same time.

J.James said:

This is true, now that I understand that your source water is the issue let me do a little digging in my notes and see what the guys over at buildasoil recommend on the subject.

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Don't get me wrong my water is amazingly pure and great tasting. Ppms under 100 but yeah very high ph.

J.James said:

Lemon juice or vinegar is what they recommend so that falls in line with your original citric acid comment. This WCA might be exactly what you need to balance everything out and add the Calcium you need at the same time.

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Awesome thanks again man!!!

Great thread. I made some Water Soluble Calcium a while ago. Didn't use it much because i've been top dressing with gypsum.
Mine reads about 8800ppm.

JHake said:

Great thread. I made some Water Soluble Calcium a while ago. Didn't use it much because i've been top dressing with gypsum.
Mine reads about 8800ppm.

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Very nice, I think I could have cooked mine a little longer and some people suggest grinding it up finer for better results. I take the easy route and just broke them up by hand.

J.James said:

Very nice, I think I could have cooked mine a little longer and some people suggest grinding it up finer for better results. I take the easy route and just broke them up by hand.

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I use egg shells for orchids. No issues my soil. Way easier way. Just use hard boiled egg shells. Sterile from the start. Dry on parchment paper 250F oven. Put a dust mask on and pulverize to fin powder in a mortar and pestil. Avoid dust. Abrasive and possible hazzard. Use as a dry amendment. Stores in airtight container for years. If looking for liquid. A 1/2 tsp of vinegar to a gallon of water. Slow simmer until water is reduced by half. Strain shells out. Not rocket science. Crazy cat lady in a trailer showed me. LMAO.
Peace all.

Have you considered using Kefir?/! All fats are removed and the calcium is in a soluble form. . .
I am planning on culturing my own so I can feed it regularly. Also you get the bennies of the microbiology if your making it yourself or you buy unpasturized.

For the non believers here’s a link

JMcG said:

For the non believers here’s a link

https://www.ctahr.hawaii.edu/oc/freepubs/pdf/sa-10.pdf

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Thank you for the link. It's in my favs now.

can you use apple cider vinegar to make wca ?