This document specifies a method for laboratory measurement of the pH value in liquid microbial plant biostimulants, using pH electrodes with a glass membrane.

From the scope of this document plant biostimulants other than microbial plant biostimulants are excluded because there is no essential requirement in the Regulation (EU) 2019/1009 [1] for measuring the pH of non-microbial plant biostimulants.