The effect of LED lighting, fertilization rate and gibberellin application on geranium (Pelargonium x hortorum) 'Red Maverick' plants in a greenhouse setting was evaluated. Seeds were germinated in 288 plug trays, transplanted to 3-1/2 inch geranium pots in a peat-based media (ProMix) and grown in a greenhouse environment. Twelve treatments consisting of plants that received either no, 150 ppm or 300 ppm 20-20-20 weekly fertilizer applications following transplant, abmbient or LED (Phillips Red/Blue) greenhouse lighting, and a treatment of either no or 10 ppm gibberellin A3 (GA3; ProGibb) were evaluated by recording weekly height measurements, pH, electrical conductivity (EC), and floral bud appearance was recorded for each treatment. The tallest, most advanced plants were obtained from ambient light, high fertility and ProGibb application with the shortest plants were produced by the ambient light, no fertilization, and no gibberellin application treatment. Visible bud was first noticed in the LED light grown plants at low and high fertility with and without gibberellin application. The results of this study will aid greenhouse growers producing geranium crops under different greenhouse lighting conditions to consider fertility rates and gibberellin application to decrease the production time of geranium crops.
