Prolly a stupid question, but I just wanted to know real quick if rockwool plugs have a shelf life? A friend of mine has some rockwool plugs but they are a year old... still good to use?

if they have been kept in ziplock bags they should be ok.

They haven't been in a sealed bag... any opinions? Or any little tests or ways I can tell if they're still good (lol, w.o putting a clone/seed in it)

I couldn't tell you, were they kept indoors at least?

Yeah, the package was open and in a plastic bag, in a cardboard box, in a closet, LOL.. it wasn't tied or sealed tho...

I would think they are ok. You may want to dunk one in water and see if it grows anything on it after a few days. (Without a seed)

LOL....! Good point. will do, thanks hon.

I used some old rockwool and had a problem with mold. not sure if age had anything to do with it, but I had never had mold before. I used cocotech this time...