Irrigation management key to growing Honeycrisp

Tom Auvil, left, listens as Jim Divis, right, discusses Honeycrisp challenges during a Honeycrisp field tour. (Geraldine Warner/Good Fruit Grower)

The need to carefully manage irrigation of Honeycrisp apples is one of the things Jim Divis has learned after growing the fickle variety for more than a decade.

Divis, of Brewster, Washington, has 50 acres of Honeycrisp out of 180 acres of tree fruit. He is a grower as well as general manager of packer-shipper Honey Bear Tree Fruit Company that’s affiliated with Honeybear Brands, a vertically integrated tree fruit company with orchards in the Midwest, Washington, and Southern Hemisphere.

“I thought I had this crazy variety figured out,” he said. “But this variety is pretty humbling. I’ve spent the last two years trying to repeat earlier quality and yield performances, and I can’t.”

Divis shared what he’s learned about the challenging variety during an educational session on Honeycrisp production, harvest, and storage coordinated by Washington State University Extension and the Washington Tree Fruit Research Commission.

Although Divis has picked 100 bins per acre from orchards with medium density (600 to 700 trees per acre) grafted on vigorous rootstocks, he admits that such feats are hard to repeat.

His orchard is trained to the steep leader and spacing is 5 feet between trees and 13.5 feet between rows. “Production of 70 to 80 bins is repeatable, but I’m having a hard time repeating 100 bin levels,” he said.

One thing he has learned is that Honeycrisp dislikes excessive water and excessive heat. Brewster, located in north central Washington, is a cooler location than some in eastern Washington, but apples there still need overhead cooling and protection from sunburn.

Divis uses fogger emitters for his overhead cooling, and he applies irrigation based on soil moisture measurements.

“We switched to fogger overhead cooling so that we aren’t dousing the trees with excess water,” he said. He’s also integrated his soil and nutrient program with irrigation management to ensure nutrients aren’t being lost by soil leaching. He applies an ultra-violet sunburn protectant to the fruit.

Today’s technology marries soil moisture measurements with smart phone and tablet portability to make monitoring user friendly.

Divis uses the irrigation management program provided by a consulting service that incorporates dielectric capacitance soil moisture probes with data loggers to provide real-time information that’s delivered via the Internet.

Soil moisture levels are combined with ET (evapotranspiration) rate, weather data, crop growth, and other factors that influence irrigation.

“My soil moisture is updated every day, and I have an app on my smart phone that shows me where we’re at,” he said. “I look at the graphs every Monday with my team, and we decide if we want to put on a full set, half, or skip irrigation completely for the week.”

He estimated that, over the last two seasons, he has reduced the irrigation amounts by half in his Honeycrisp blocks. For much of the summer, he now irrigates six-hour sets instead of what used to be 12 hours. He credits the reduction of irrigation for helping improve his Honeycrisp fruit quality.

When Divis first began growing tree fruit in the mid-1980s, he used ceramic-tipped soil probes to help him monitor soil moisture. “But today’s technology has made monitoring so easy. Now, we have all the information at our fingertips on our cell phones.”

Nutrition changes

Divis also changed his nutrition program for Honeycrisp. His yearlong nutrient program begins with a postharvest soil test, with amendments made in fall or spring according to the sample results.

In spring, a mineral analysis is run on fruitlets, with foliar applications of nutrients, including calcium chloride based on the fruitlet analysis.

In mid-summer, he takes another soil sample, applying amendments if needed. Prior to harvest, fruit are sampled again for minerals.

“I want my soil moisture and nutrition to be working together,” he said, explaining that he’s careful not to drown soil microbes (which need to be working to remobilize minerals and nutrients) from too much water in early spring. He starts spring irrigations three weeks later than some of his neighbors.

Good, bad, and ugly

Divis tags each Honeycrisp bin at harvest with red, yellow, or green bin tags to denote storage potential.

Fruit with red tags are run over the packing line first and are first in line for shipping. ““We run the ugly fruit (red tag) as fast as we can, so we can ship it down the road,” he said. Yellow tags go next and the good fruit (green tags) are held in storage for strategic marketing.

By tagging bins at harvest, the packing house receiving crew knows how to manage the fruit, he said, and added that growers who take the option of long-term storage do so at their own risk and stand alone in the grower pool. Some don’t want to take that risk of low packouts.

The bin tagging requires extra data collection, record keeping, and management. “We have 30 different lots of Honeycrisp that we have to identify and categorize at harvest,” he said. A host of factors go into deciding the bin tag color, including block age and history, crop load and fruit size, maturity/storage index at harvest, fruit starch, pressure and acid levels, and grower willingness to take risk. •