In the process of cleaning up my orchid area so I can get seriously into growing again, I discover that I have, shall we say, a few bottles of various types of fertilizer of unknown vintage.
None of them have any sort of expiration date stamped on the bottles, and they've been stored (well-sealed) in a cool, dark area. Should I just toss them and plan on buying new? Or are they conceivably still "good"?