Realize maximum yield potential in tart cherries with gibberellic acid
Reduce blind wood and regulate cropping potential with gibberellic acid.
Cherries have a natural tendency to produce “blind wood.” This phenomenon is associated with the flower bud formation on the young wood, so after the harvest, we are left with long bare spots with no spurs. Research done by John Bukovac showed that it is possible to manipulate the flower bud formation in favor of spur development by applying the gibberellic acid.
When do we apply gibberellic acid?
If you are used to going by the calendar, general recommendation is to apply the spray three to four weeks after full bloom. Perhaps, more accurate timing would be when you have five to seven fully developed leaves on terminal growth.
Gibberellic acid will induce spur development, thus reduce “blind wood” formation and provide greater bearing capacity. How much of “gibb” you need to use will be the function of the tree vigor. High vigor requires low rate; low vigor demands higher rate.
Material: Pro - Gibb 4%
Rate: General recommendation is 10 to 25 ppm.
10 ppm = 4 oz. / 100 gallons of water
15 ppm = 6 oz. / 100 gallons of water
20 ppm = 8 oz. / 100 gallons of water
25 ppm = 10 oz. / 100 gallons of water
How to apply: Gibb should be applied in 50 to 150 gallons of water. For best results, apply gibb when temperature is 70°F or above. At lower temperatures, the uptake has not been adequate and the applications were less successful.
Bukovac has found that use of surfactants can yield various results; from no effect to very little effect, to over-response with phytotoxicity. Silicon-based surfactant caused phytotoxicity. In conclusion, do not use surfactants!
Young, non-bearing trees
It is particularly important that in the first few years following planting, ensure good vegetative growth. Well-developed trees with the strong framework will be able to provide you with uniform and plentiful bearing capacity.
Timing of application on the young trees is the same as for the mature trees. The difference is in the concentration of gibb applied.
To ensure almost no flowers, use 40 oz. of Pro - Gibb 4% in 100 gallons of water. If tree vigor is low, a second application three weeks following the first one may be helpful. Two applications of 50 ppm about two weeks apart are more effective than one application of 100 ppm. Do not treat more than twice in one year.
Caution: Do not spray gibb on the trees in year of planting!