I think , from what I've read, that the reason the lime kelps with both rot, and leafspot, is twofold. 1st, the lime increases the ph of the soil enough that neither the bacteria, or the fungus, can really "prosper"(which would also explain why *Comet cleanser works so well on bacterial rot...besides the "bleach" which is anti bacterial, the "soap" raises the ph), and secondly, I think, in most cases the ph in our beds is "too low" (too acid) because of the fertilizers we use, and raising the ph ...to the proper level...makes the plant healthier, and thus, more resistant to disease
