Check Your Containers
Containers or flower pots are available in many shapes and sizes (dimensions and volume) and made of various materials. Their function is straightforward – contain the substrate and thus, nutrients and water for optimal root growth and development. Most all containers used in bedding plant production have drainage holes which allow irrigation water to drain from the substrate pore spaces. However, there are instances where containers are defective and drainage holes are sealed with a thin layer of plastic from the manufacturing process. This defect is likely unknown by the grower and overtime, the substrate will become saturated.
Recently, the Owen Lab encountered this situation where a thin layer of plastic covered the drainage holes of containerized coleus. We were unaware of these defective containers until it was too late. Plants grown in the containers with sealed drainage holes appeared to be wilted or have flagging leaves. Plants were stunted and most had small root systems that smelled of degradation. Using a pocketknife, we punched the thin layer of plastic that cover the drainage hole. Although we disposed of these plants, it was a perfect learning experience for my students. Moving forward, we will be checking all containers to ensure the drainage holes are present prior to filling with substrate and to never assume a wilted or flagging plant needs water without checking. Though I realize checking the presence of drainage holes in each container may not be feasible for most growers but is worth noting because I have come across similar situations during my Extension travels.
W. Garrett OwenAssistant Professor and Greenhouse Extension Specialist , University of Kentucky
W. Garrett Owen is an Assistant Professor and Extension Specialist of floriculture, greenhouse and controlled-environment crop production in the Department of Horticulture at the University of Kentucky. He has an appointment in research, teaching and Extension. His area of expertise is controlled environment specialty crop production; plant nutrition; plant growth regulation; and production problem diagnostics.