I have some 5 - 6 year old general hydroponics nutes? do they have a shelf life? I would probably be better off buying fresh stuff but I have a couple bottles of it.
I have no idea....wonder about this myself.....I grew once about 3 years ago and the grow did not go very well but I did buy a ton of nutes at the time......then I just started my second grow in Dec. 2008 (which is going much better so far) and when I opened up the nutes I thought they did not smell right so I scrapped everything and bought new stuff.
if the nutes are kept at a constant temperature and aren't exposed to light then the guys at Growth Technology reckon that "clear" liquid type nutrients will last easily up to 5 years best way to test is to decant the liquid out and check for salt crystals - if you see any crystallisation at all then dump the nutes and buy fresh hope that helps