This might be a silly question, but I thought I would throw it out there and see if Tim, Matt, or someone up on the subject might be able to comment.
In one of my day jobs, I formulate pet feeds and supplements. I have been using Calcium Propionate (Calcium salt of Propionic Acid) as an ingredient for some of my products. I use it along with methyl paraben, and Potassium Sorbate (salt of soribic acid) and Citric Acid (to adjust PH) for the inhibition of rope bacteria, mold, and yeast in the formulas which are served mixed with water. I use the Citric Acid to adjust the PH of the final formula to around 5.0 because these acids work much better at a PH of 5.5 or below.
Calcium propionate is quite soluble in water (400 grams per liter) and about 23% calcium. A 1 mole solution contains approx 41 grams calcium per litre and a saturated solution would contain about 85 grams per liter. It costs about a dollar a pound in a #50 bag.
I do realize that Calcium Nitrate is a great source, but was just curious about the concept of using Calcium Propionate as a source of Calcium that would allow you to use it with a more readily available complete fertilizer formula since we don't seem to really want a lot of nitrogen. Using Calcium Nitrate in combination with most formulas gives us a more nitrogen than we want, so we have to use it with low nitrogen formulas, which are hard to find ..... or the possibility of it's use as an anti fungal.
The ability of it to retard mold and yeast (fungus) seems interesting. It is used in drosophila media at approx 5 grams/litre (.5%) and totally retards mold and rope bacteria growth for more than 30 days in a solution that is 80% sugars DMB...... I couldn't find anything on the web about it being used as fertilizer or an anti fungal.... but the concept is interesting to me and I wonder why I can't find any info on the concept, good or bad.
I know..... I probably have better things to think about LOL. I just like thinking outside the box.
Bueller?