I believe that the shelf life of the mineral fertilizer is indefinite. The only thing that could happen - it could absorb water - then dry - and turn itself into a fertilizer brick.

As far as I know fertilizer does not "go bad." But they do make sales on it in late autum which tells me either they need the space or they want to get rid of the old fertilizer.

I think it lasts forever.

As Irene says, humidity or water will make it very hard but you can scrape it with a fork and still use it.

Nancy

Email the company and ask!

Hi everyone,
Thank you for the repiles
Interesting.
Maybe I will email the company.
I understand that Peter's changed its formula a few years ago. Now it has urea.
This "older" Peter's is the good stuff! And it hasn't turned into a brick yet either!