Influence of Lime Type and Rate on Pine Bark Substrate pH.

Pine bark substrate in the southeastern U.S. is the substrate of choice for ornamental plant producers. The low pH of the unbuffered substrate needs to be adjusted with a lime material in order to promote proper nutrient uptake and ensure general plant health to avoid abiotic disorders. The research and data collection from this study evaluated the long-term effect of four lime materials and five rates on the pH of a pine bark substrate that was planted with rooted holly cuttings over nine-months. We found that pH is raised by lime material and rate over time, with >4.5 kg•m-3 needed to maintain an optimal pH for ornamental plant growth. Our data along with past research on the subject will benefit producers in using the proper lime material and rate for optimal plant health and to prevent abiotic disorders during crop production.