Daily Light Integral Impacts Vegetable Transplant Quality
Vegetable transplant quality can be improved by providing an optimal daily light integral (DLI) of 10 to 15 mol·m–2·d–1. To do so, growers must implement a lighting strategy that manipulates light quantity (intensity) and duration (photoperiod) such as supplemental day-extension lighting. However, this may not be feasible for all. Keeping the glazing material clean, limiting overhead obstructions, retracting shade curtains, or removing white wash are some light management strategies that can increase light transmission into the growing environment while maintaining low electrical costs. Under low DLIs, transplants will often be poor quality, exhibiting reduced root growth and weak, elongated hypocotyls that can be easily broken while handling. Under higher DLIs, root growth increases, and transplants are compact with short, thick hypocotyls and smaller leaves which are less likely to be damaged when handled.
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.