Epson salts and high light plants

[Ray]

Originally Posted by neophyte

I don't think it would. Magnesium doesn't exactly help a plant produce chlorophyll, it's simply a component of the chlorophyll molecule. When the plant is bleached, it's not losing the magnesium; it's just that the magnesium can't stay in the chlorophyll and has to go elsewhere. So adding more won't really make a difference because there is no deficiency.

Here's a weird analogy: if you're trying to store water in buckets and the buckets disappear, it won't help to get more water because the buckets are gone; you need to buy more buckets.

Yes, and adding more water doesn’t create buckets!

Similarly, supplementing with extra Mg doesn't reduce bleaching because the Mg won't end up in chlorophyll. In fact, overdosing on Mg can actually lead to more damage (due to toxicity).

I’m going to have to temper that statement. Mg toxicity is very rare. Mg is very loosely bound, so damned near every other cation out-competes it for uptake and placement in tissues and excesses are very easily dumped by the plant. I have applied as much as two tablespoons/gallon without issue.