Knowledgebase
shelf life of granular plant fertilizer #751347
Asked May 21, 2021, 4:17 PM EDT
I have several boxes/jars of granulated plant and vegetable fertilizer that you mix with water. Such as Miracle Gro or Shultz. I don't go through much each and would like to use it up.. But if it is losses it potency, I think I'd better invest in new. I would so appreciate your advice on these products, how long they last, best way to store them, etc.
Thank you,
Sibyl
Kent County Michigan
Expert Response
Hi Sibyl,
Great question! There are a couple of rules of thumb that people use:
- Stored properly, granulated fertilizer has a very long shelf life
- Liquid fertilizer may lose its potency after 10 years on the shelf
Unfortunately, I haven't been able to find any university-based research on the topic, so it's difficult to evaluate whether those statements are true. Perhaps the manufacturers could provide an answer?
Nevertheless, I have to imagine that the shelf life of granulated fertilizer is longest when not exposed to air and moisture. The best practice would be to store it in an airtight container in a cool dry place.
To answer your question: your fertilizers are probably OK to use. Assuming they were stored reasonably well, I would feel comfortable using them on my own plants.
