Question
Hello,
I was wondering if I can use my slow-release fertilizer from last spring when I plant this spring?  Does it expire?  How about the other fertilizer?  THANKS!

Answer
Fertilizer can be used for many years without risk of expiry provided it has been stored dry.

I recommend sealing the bags in fall with a good quality tape for the winter. Store in a dry garage or basement. While temperatures have no direct affect on fertilizer during storage, try to avoid storing fertilizers where they are exposed to temperature extremes (especially heavy freezing).

Check the fertilizer in spring. Provided majority of the pellets are whole, you can apply. If a large part of the pellets are broken, then do not use (especially for slow release versions).

I have large fertilizer bags which are 5-7 years old and still good.