I have not located the original posts supporting this idea, but I do have to wonder if something else is going on. As a plant physiologist, I have trouble believing that you could get enough calcium into a cut flower, in so short a time, to make any difference. On the other hand, the citrate could be used by the flower as a source of energy, and we know that helps -- commercial flower preservatives almost always have citrate in them for precisely that reason. Also, those preservative solutions almost always strongly acidify the water, which makes we wonder, again, about a calcium-based substance that would at best be neutral pH, but in most cases, alkaline. So I'm wondering if the effect being seen here may be due to the citrate. That would still leave the question of why Tums works (CaCO3) -- I tend to doubt that it does, but as I said, have not found the reference about it. Over the years, we've done quite a lot of research on floral preservatives. Generally the often-recommended aspirin has no effect at all. One of the best materials we ever found was one part Sprite (regular, not diet -- you want that high-fructose corn syrup!) to 3 parts water, then with a couple drops of Clorox in a quart of the solution. That mixture gives excellent life to cut flowers. Sprite has citric acid (Hydrogen citrate), simple sugars, and is rather acidic -- the three things we want in a preservative solution.

Magnesium issues can be a problem on some plants and a cause of chlorosis on unfertilized or underfertilized ones occasionally and hardly a myth, but certainly quite uncommon. You can look up the symptoms online, but as a general rule, any time plant leaves start to yellow, it's time to do some digging (so to speak!) So I keep a small bag around and have for the last decade, but I can absolutely state I've used about five ounces out of it in that decade, including the entire property of 12,000 square feet total. If you're using most versions of Miracle-Gro to fertilize, Mg shortages shouldn't be much of an issue, nor should any lack of green leaves. But still, underfertilization may occasionally rear its ugly head. As a general rule, low nitrogen, iron, or magnesium problems can all be a cause of yellowing leaves (among many others, but those tend to be the primary resource-related ones, in that order), so definitely go investigate if these are showing up on your plants. But never, never blindly toss Epsom salts or any other resource on plants just to cure a problem that isn't there. Magnesium can cause tightening of soils, even very loose and sandy ones, and that's the last thing you want in a succulent pot or any other soil. Too much magnesium also make it harder for the plant to absorb some other resources if amounts rise too high due to simple resource antagonism. I tend to follow the "feed weakly, weekly" method on most plants during their growing seasons because simply put, it works and maintains a constant regular flow of nutrients. If the plant doesn't want it, it has ways of letting you know. If it does want it, it also has ways of letting you know--usually by not growing and turning funny colors. I'd rather avoid that, thanks. But I also tend to avoid that on anything but N, P, and K and only allow maintenance levels of anything else to avoid some of the discussed problems above. So you can walk a fine line over the years even feeding regularly. That's why regular repotting is recommended--and why some of us do some organic feeding even in our pots.

Yep thats what I do too Mike and every few weeks I give them a foliar spray of compost tea early in the morning. Daniella, I buy my compost tea at an organic nursery already made up but I got the stuff to do it myself now and saw on the garden show how to do it using an old panty hose leg or cheesecloth to hold the compost then you don't have to strain it. I mix the fish emulsion with this when I spray. I don't always have time to go do all that individually to all the plants so I just do it when I have the time.

One of the university sites, in response to an Epsom salts question, stated: "...there is no harm in trying and see what the result is. Just don't overdo it, as we Americans typically do so many things!" Here is a link that might be useful: Results of search for Epson salts and .edu sites