*just having some coffee and thinking....
There are lots of stories on this website, in regards to "What's wrong with my plants?" And much of the time, they post pictures of leaves that have some spots on them...."CALCIUM DEFICIENCY!"....Or, pictures of plants with red stems...."MAGNESIUM!" But it's difficult to understand how a small plant in a fresh batch of, say, FFOF or FFHF (or a mix of both) could be deficient. If anything, FFOF is considered to be kind of "hot". How could a 1-month old plant in a 3-gallon pot, be deficient? Just by deductive reasoning, you could rule out deficient soil. What does that leave? There is a strong possibility that the symptoms of a deficient soil mix is, in fact, a pH lockout issue. But, few people have a $400 pH pen or they don't know how to use one if they did have one!
And, as with this thread, there are people who actually advise to NOT check it via runoff....which I just don't agree with at all. pH checking via runoff might not be considered as much as it should be, in my opinion.
I get that an organic "soil" mix
should be able to generate symbiotic relationships and balance itself in terms of pH....but, then again, sometimes, it doesn't. It's like living soil -except dead. Maybe it could be "jump started" by top dressing or whatever....but that takes time. When your plants are sick, you don't have time.