Does fertilizer expire?

I have a little jar of Schultz powdered orchid fertilizer, which I got
a year ago, & have used very little as I only have a few orchids.
There's no expiry date on it; it says changes in colour & texture don't
affect potency, & it has changed colour & got less powdery & a bit more
clumpy since I got it... but I was wondering if this stuff keeps
indefinitely or what? It will take me forever to use it all up -- I
just don't have room for enough orchids to use much! :(

Alison

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