White patch mold with humidity at 16% ?

I have noticed that a lot of gardens get white patch mold on the leafs i was told that once you see it on the leaf its been in the plant for at least 2 weeks. So what is are methods to get rid of this problem, or at least detour it so there is little to no signs of it at all thanks for any replies.

Are you sure it's not Crystals? I don't know very many molds that can grow in such low RH. Maybe your RH monitor is busted?

Thanks for the reply but the humidity is a digital read out from 2 different units and they both read the same and ya there not crystals because i have never seen crystals on the leafs ment for breathing and absorbing light the little leafs yes but the big ones i always have my ph at 6.0 to 6.3 and its bottled spring h20 not tap.