A word of caution! This is a progress report of our research and NOT a recommendation to use the method. You should follow label instructions: this method is not described in the Bonzi label yet. For more information, call Dr. Pasian at 614-292-9941 or pasian.1@osu.edu.
Some crops, like marigold, tend to stretch very early after germination especially if grown in low light environments. By the time the growers apply growth regulators (PGRs), stretching of the hypocotyl has already occurred and sprays are ineffective. We wanted to test whether it was possible to control plug height by using the seed coat as a PGR carrier.
Marigold 'Bonanza Gold' and geranium 'Cherry Orbit' seeds were soaked for 6, 16, and 24 hr. in Bonzi solutions of 0, 500, and 1000 ppm. After imbibition, seeds were dried for 24 hr. prior to sowing in plugs. Seedling height and % emergence were measured 16, 26, and 36 days after sowing.
Increasing Bonzi concentrations (1000 ppm) and the imbibition time produced shorter seedling, reduced emergence of geranium, and inhibited plant growth excessively. Thirty six days after sowing, marigolds measured 8.5, 8.6, and 8.6 cm high when imbibed in water for 6, 16, and 24 hr., respectively. When PGR was used at 500 ppm, seedling heights were 6.5, 6.1, and 6.2 cm, respectively.
Similar or even greater reductions in height were observed for geranium. These preliminary results indicate that this method of PGR application (especially the 6 or 16 h soak in 500 ppm Bonzi) may benefit plug growers of marigold and other crops prone to stretching (Cosmos spp.).
