How You Can Determine Substrate pH in Plugs and Liners

Plug-Press- substrate pH

Photo credit: Garrett Owen, MSU

It is not uncommon for greenhouse growers to use in-house nutritional monitoring methods to determine substrate pH and soluble salts, referred to as electrical conductivity (EC), levels. Most often, these procedures are performed on plants produced in their final containers and rarely on plugs or liners.


So how do you monitor substrate pH and EC of plugs and liners? In a post on Michigan State University (MSU) Extension’s Floriculture and Greenhouse Crop Production site, MSU’s Garrett Owen suggests growers either conduct a PourThru or utilize a press technique or plug press.

Owen’s report includes a link to a video on conducting a pour-thru, and a step-by-step process for conducting a plug press.

Check out Owen’s tips here.