Calcium itself isn't the buffer, but Calcium Carbonate specifically. Calcium amendments do not buffer pH unless they are Calcium Carbonate, think Oyster Shell, Dolomite Lime, and even egg shells to a lesser extent. I would imagine crustacean meal of any sort has some pH buffer, but only because it is in their shells. I cannot say for absolute certainty on that one, personally. Maybe someone else knows for sure.
Calcium Carbonate will buffer and provide nutrients, something like gypsum will only provide nutrients.
I've never experienced adverse effects using Epsom Salts, and I've only ever experienced mold with outdoor plants due to caterpillars being assholes.
I've not only never seen a S deficiency in my own garden, but I've never witnessed it in other people's gardens or even heard of anyone dealing with one!
I started foliar feeding with the Epsom Salts upon reading these articles. I noticed a difference in my final product immediately, and have done so ever since. Epsom Salts actually contain more Sulfur than they do Magnesium.
Sulfur is the third and final secondary plant nutrient. During the vegetative growth phase of your cannabis plants, sulfur is a vital building block of chlorophyll.
www.marijuanatimes.org
The accumulation of plant defense metabolites is closely associated with the concentration of nutrient elements, yet data related to the interactive e…
www.sciencedirect.com
"During Cannabis flowering, sulfur is vital to oil production and certain terpenes, such as limonene. "
"The volatile products from d-limonene contained some aromatic hydrocrabons but consisted mainly of sulfur compounds."
"Essential oil composition was altered by changing Mg and Mn levels. Deprivation of Mg also decreased the proportion of sesquiterpenes in the
essential oil."
It would seem that the second article is referencing the first article I linked; the first article is a scientific article that appears to back up the claims made in the second article.
I will readily and freely admit, without these articles the idea of foliar feeding with epsom salts to increase flavor/terpenes is borderline stoner science.
However, the above articles in conjunction with the fact that most "terpinator" products on the market (not that I've ever used them) are mostly sulfur (terpinator = 95% Potassium sulfate, silver bullet = 98% sulfur, etc.), as well as my own (and many other's) personal experience has confirmed this as truth.
There's the Mg and S that a plant needs, and there's the Mg and S that the terpenes themselves need. Foliar feeding epsom salts isn't so much to fix deficiencies, but to provide extra for the plant to take advantage of.
I've always thought of Epsom Salts for plants to be similar to Protein for humans. Humans only need a minimum of ~.36g of protein per pound, however this number becomes doubled to ~.70-.80g of protein per pound if one is trying to build muscle mass. So, humans don't
need more than .36g of protein to survive but they can certainly make use of excess given proper conditions.
With that in mind, this is my
theory concerning Epsom Salts. Again, its just that, a theory. A stoner science sounding theory. All that I have is my (and other's) personal experience with Epsom Salt foliar feed's effects on flavor/taste, but that's it.
While the articles I listed above don't explicitly say "Epsom salts = more terps", they do explain a correlation.
It is worth mentioning, that studies related to terpenes themselves are still fairly new in the grand scheme of things. We've only just begun to scratch the surface in terms of terpene related research, and the only real reason any research pertaining to terpenes has been done is because of cannabis it seems like.
tl;dr: Epsom salt foliar feeds are not to cure deficiencies, but to aid in "bulking" terpene production. Try a side by side and see for yourself.