For the last few years l've been saving all our egg shells, drying them in the oven by pilot light, using a coffee grinder to grind them into powder and then adding them to the tomato plants' soil. I realize others dispute this but my own informal testing and anecdotal experience has demonstrated to me that it does make a difference.. a considerable one at that.

Recently, I've been considering possible methods to, either, extract more of the calcium carbonate or break it down to make it accessible sooner. I know that vinegar can dissolve the shells to release the calcium carbonate but I also know that vinegar can act as an herbicide.

• Is it the acetic acid or something else in vinegar that makes it harmful to plants?


• Does the interaction with the calcium carbonate neutralize vinegar's deleterious effect?


• If not, is there another element that could be introduced that would neutralize vinegar's herbicidal properties while retaining (or possibly even adding to) any beneficial elements?
  (just enough baking soda to balance the ph, for example?)

Thanks for any input

I said all that to say this: Adding vinegar (acetic acid) will soften the concretions over time. So, to answer your question, if asked in reverse: Yes!

Adding any kind or any amount of acid to your hydroponic set-up will drastically affect the pH!

Hope that helps some.

Vinegar is a dilute acetic acid. Acetic acid is what hurts the plants. Concentrated forms of it are sold as more environmentally friendly contact herbicide which you can read about here:

http://www.pesticide.org/pubs/alts/weeds/vinegarinherbicides.html

This source says the acidic qualities destroy the cell walls if the acetic acid is sufficiently concentrated. Spraying the vinegar we keep in our kitchens may not do the job for much more than small juvenile weeds.

If this were indeed true then calcium carbonate should diminish the effect. The acetic acid would form partially into calcium acetate and neutralize it's acetic pH. Calcium acetate's pH is about 7.5, according to this MSDS.

http://www.jtbaker.com/msds/englishhtml/c0266.htm

According to wikipedia calcium acetate is used as an additive in candy. Who knew? You could try mixing acetic acid with classroom chalk or tums, then applying it to a plant and/or soil and see what happens. If you use baking soda you will be introducing some sodium which isn't going to be desirable.

"I get soluble calcium by dissolving sea shells in vinegar. Let ±50g of shells soak in 1 liter of white vinegar. After about 24 hours you can boil the lot in a stainless steel pot for about an hour. Then filter the liquid (I use a coffee filter [LOL]) to remove the excess of shells and make-up the volume to 1 litre.
This way you obtain a calcium acetate solution that contains 15 grams of calcium per litre."

"? Are you able to estimate the grams of Ca that egg shells, substituted for sea shells, would yield in your formulation ?
(The egg shell in vinegar extract, for soluble calcium, was told me by an old country doctor over a quarter of a century ago for use as a human nutritional supplement of calcium.)"

"It would be the same.
The amount of calcium(Ca) that will dissolve as acetate in 1L of white vinegar (5%) - irrespective of its source - is ±15g (in theory: 16.7g).
Just dissolve egg shells untill they no longer dissolve."

"when making the calcium acetate, is boiling required? and what does that part do? I was thinking of just dumping egg shells and vinegar into a glass bottle then skimming liquid off the top as needed as a calcium supplement. since the concentraition will always be 15ppm, the idea is just get as much as required for the concentration I want to make up."

"I suppose that could work. The boiling is intended to remove any residual acid. Maybe you should test the pH to make sure(?)"