Lime Calibration for Soilless Media- A Tool for Greenhouse and Nursery Producers

Abstract

Rootzone pH is important to manage to produce marketable nursery and greenhouse stock. This is primarily because mineral nutrients are more available under certain conditions (within specific pH levels). Soilless substrates are essentially inert and contain little nutritional value. Thus, the producer is responsible for supplementing nearly all applied mineral nutrients and water for proper plant development. This goes beyond simple fertilization, where maintaining optimal rootzone pH levels is critical to ensure that applied nutrients are available to the plant. If not, plants can exhibit symptoms of nutrient deficiency or toxicity, resulting in delayed or decreased yield or reduced quality. The first step in ensuring that rootzone conditions are healthy for the plant is gauging the current pH status of the rootzone and correcting it through proper lime adjustments. This extension article highlights the importance of rootzone pH in soilless substrates and explains how to adjust rootzone conditions prior to production by performing lime calibrations.