Did you flush your soil?Thats the first thing you shoud have done.
Thats a big ph flux....maybe that did it.
My question for you is...you are growing that for medicine and you just got a ph meter? Can you tell me what co-op ,so I don't go there?
I'm not trying to dog you...just the co-op.If they are hiring newbie's to grow there med's,I'd like to not waist my money. Sorry if I sound like a dick,I just don't like ppl taking advantage of sick ppl.(the co-op)