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Lower Leaf Yellowing and Purpling in Spring Pansies

Wed, Mar 6th, 2024, created by W. Garrett Owen

Over the past few weeks, the Midwest has experienced many cool and rainy days. These conditions create an opportunity for lower leaf reddish purpling to manifest in early spring crops such as pansy (Viola wittrockiana). While on a recent grower visit, I noticed lower leaf yellowing (chlorosis) and reddish purpling. When these symptoms arise, you should first inspect the roots or submit samples to your preferred diagnostic lab for pathogen testing. In-house, you can perform a PourThru to determine the level of soluble salts [referred to as electrical conductivity (EC)]. Low substrate EC often causes lower leaf chlorosis. Target substrate EC levels for pansies range between 1.3 to 2.0 mS/cm based on the PourThru method. Providing 100 to 150 ppm N should prevent lower leaf chlorosis. Additionally, maintain a substrate pH of 5.5 to 5.8 based on the PourThru method. Lower leaf purpling is often attributed to the lack of phosphorous. In this case, cool air temperatures and saturated substrate with limited fertility likely induced the symptoms. Drying out the substrate, increasing growing temperatures, and providing proper fertility will help correct this disorder if a pathogen is not suspected. For crops grown outdoors, frost blankets or floating row covers work well at night or during cold snaps.

About the Author:

W. Garrett Owen

Assistant Professor of Sustainable Greenhouse and Nursery Systems, The Ohio State University

W. Garrett Owen is an Assistant Professor of Sustainable Greenhouse and Nursery Systems in the Department of Horticulture and Crop Science at The Ohio State University. He has an appointment in research, teaching and Extension. His area of expertise is plant nutrition; plant growth regulation; and production problem diagnostics.

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