but it’s a manual, labor-intensive process. Measurers cut off a leaf, place it into a pressure chamber and apply pressure to it until water comes out of the severed trimming. Because the method is time-consuming and slow, growers don’t use it often. Neither does it provide a continuous picture of the plant’s health, Lakso says, likening the process to taking a blood pressure on a patient once a week. “It tells you what it is, but it doesn’t tell what it was the week before,” Lakso says. “I wanted to have a way of monitoring plants continuously.”