We had Dr. Joan Davenport back again this week for her annual summer visit! Joan comes to see us in the spring during the bloom period and again in the height of summer to discuss fertilizer needs for bud set.

Additional nutrition is necessary because while cranberries have adapted (and thrive) in their native sandy soil, nutrients are taken from the bog through the harvest of fruit. The three main elements usually added for nutrition are nitrogen, phosphorus, and potassium. “This late in the growing season, we are assessing the new plantings for nutritional needs but also for when to stop fertilizing, so that the plants will enter dormancy,” Joan says. “For established beds, we are evaluating the plants for how much crop they are holding and the bud potential for next year to develop recommendations for applications for the remainder of the growing season, including post-harvest and some guidance for roughneck in the spring of next year.” To do this, Joan and the PIICM team look at the amount and size of fruit, the length and color of both new and upright growth, and the amount of buds already set.

This season Joan sat down with our ICM team to discuss crop needs for fertigation, a process where plant nutrition is distributed via the irrigation system, and the extra care we’re going to need to take with our hardware and equipment, particularly with the sprinkler heads. Her recommendation for certain beds under review was to continue for another year. “One season doesn’t tell me how things will continue to respond,” she says. “Realistically, we start seeing results after a two year cycle when the same beds are being run on the same program in terms of hybrid versus strict fertigation.” She also had some recommendations for spacing.