How long will PGR's stay effective in a water solution?

Asked July 1, 2015, 2:37 PM EDT


I am considering making a stock of PGR solutions so we can quickly respond to plant needs. I know with herbicides, the rule of thumb is to use a solution in about 12 hours. Is this the same with PGRs? Has anyone done any studies on the efficacy of PGRs in solution after hours or days?

Thank you for your time!

Clackamas County Oregon

1 Response

The efficacy of PGR after a time in solution will in general depend on temperature and pH of the solution and the PGR in question. It general it is better to use it quickly rather than to store it. For instance, gibberellic acid (GA) slowly undergoes hydrolysis in water with a half life at 67 F of 14 days. Shorter times are expected if the solution is acidic. Using within 12- hrs would be a good rule of thumb but you may want to verify the half life for each PGR in question.