This post was written by Fadi Al-Daoud and Cara McCreary, greenhouse vegetable specialists with OMAFRA, and originally appeared on the ONgreenhousevegetables blog.

The quality of water and nutrient solution used in controlled environment agriculture (CEA) production systems, such as greenhouses and vertical farms, is one of the most important factors that affect plant health and yield. Growers monitor water and nutrient solution quality by sending samples for analysis to determine the levels of nutrients and salts. They also use sensors to monitor pH and electrical conductivity (EC) regularly to determine necessary adjustments for the nutrient solution. Growers may also analyze the microbiome, the genetic material of all the bacteria, fungi, and viruses that live in their water and nutrient solution, to evaluate levels of harmful pathogens, such as Pythium and Phytophthora species that cause root rot.