The U.S. Forest Service says rooting hormone powder will keep for 18 to 24 months if stored in an airtight container in a dark, cool place such as the refrigerator. The Forest Service advises gardeners to record the purchase date on the product container and to discard rooting hormones more than two years old.

How long is rooting powder good for?

As long as the rooting powder is kept at room temperature and out of direct sunlight, the shelf life is 3-4 years. Best by is 2 years.

Does powdered rooting hormone expire?

There is no expiry date on rooting hormones (at least not on those that I've been able to find) and in the past, the consensus was they didn't need one, because they were good for a long, long time. ... I know of professional plant propagators still using rooting hormone over 5 years old with and they have no complaints.