(I'm not sure whether or not this is the most appropriate forum in which to post. If not, please suggest an alternative. Thanks)

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?)

My intention is to then dilute it and add to waterings.

Thanks for any input