Hot tips for Honeycrisp

Growers visited the Honeycrisp orchard of Mike Robinson (right) in June and will have the opportunity to return near harvest to see the impacts of various growing practices.

Geraldine Warner

When Washington State growers began planting Honeycrisp in the late 1990s, the wisdom was that the variety would present an opportunity for those in cooler growing districts.

Art Zink was one of the first to adopt the variety at his 1,300-foot-elevation orchard at Methow in north central Washington and felt confident that growers in cooler areas would have a distinct advantage with the variety over larger operations in hotter areas in the Columbia Basin, where it would probably sunburn badly.

But with high consumer interest in the variety, ­Honeycrisp’s range has been expanding. With returns of over $100 a box, growers can afford to invest in practices to mitigate less-than-ideal conditions.

Take Mike Robinson, for example.

Robinson had a weak-growing 23-acre block of Granny Smith apples on Malling 9 rootstocks at his orchard in Othello in the heart of the Columbia Basin that he struggled to get a good green color on.

The ­decision to graft them over was easy. But to what? He decided on a red strain of Honeycrisp.

The south-facing slope is too hot for Honeycrisp and the tree spacing (5 by 14 feet) too wide for a variety that will stop growing once it fruits, Robinson acknowledges, but he’s treating it as a grand experiment. He’s trying to figure out how to grow Honeycrisp in volume so that when the price goes down he’ll be able to compete.

Grafted

One half of the block was grafted over in 2011, with two sticks of Honeycrisp wood per tree. He’s training them with a single leader on a four-wire trellis with the aim of creating a fruiting wall. He’s following the philosophy of Stemilt Growers horticulturist Dale Goldy: Push the tree as hard as you can as fast as you can, and when the tree has grown enough, stop fertilizing it in order to improve fruit color and avoid bitter pit.

The other half of the block was grafted last year, and those trees are being trained with two leaders, which Robinson thinks will be a good fit for this variety. Where one leader is growing more vigorously than the other, he’ll take the fruit off the smaller one until it catches up.

Tree training is accomplished mainly through pruning. During the first winter after planting, each branch is cut back to a 6- or 12-inch stub with a Dutch cut.

During the second winter, he cuts the one-year wood in the tops of the trees (above 5 feet) back to stubs and cuts the one-year wood below five feet to the point where it will be stiff enough to hold fruit without moving. Limbs that grow back from the stubs are usually flat and don’t need tying down. In August, before harvest, he removes unwanted upright branches.

Fertilizer

Until the trees fill the space, he’s applying 100 pounds of ammonium sulfate fertilizer in the fall, two 50-pound applications of CAN 27 (50 percent ammoniacal nitrogen and 50 percent nitrate nitrogen) in the spring, and 50 pounds of calcium nitrate in June.

To alleviate bitter pit, he applies calcium at least 20 times (twice weekly), starting with liquid formulations and then shifting to calcium chloride later in the season. Sometimes he treats only alternate rows, depending on the tree size and amount of blow-through.

In one of many experiments in the block, he omitted the spring fertilizer applications on four rows, which left those trees looking significantly weaker than the rest. He fears the trees will never ultimately achieve the same production as the others.

Yield

Most of the fruit in the second leaf is removed to encourage the trees to grow to fill the space. If Honeycrisp trees are overcropped and stop growing, they never start again, he said.

His yield target for the third leaf is 40 bins per acre, which he thinks is achievable because of the naturally large size of Honeycrisp apples. In the fourth leaf and fifth leaf, he’s aiming for 60 bins.

At maturity, he’s hoping for 80 bins per acre. “If you fill the space on Honeycrisp and you get good-sized fruit, 80 bins is a pretty easy target, particularly if you’re blossom ­thinning, because you can keep production consistent,” he said.

He’s experimenting with mechanical thinning, with the Bonner machine and ­handheld devices, as an alternative to hand-thinning blossom clusters. Until Honeycrisp becomes a less valuable apple, he’s not going to risk the uncertainties of chemical thinning, though he does apply NAA (naphthaleneacetic acid) just to the tops of the trees to remove late bloom.

Sunburn protection

To avoid heat damage, Robinson installed shade cloth that also serves as hail net (or vice versa). He has several types of cloth or netting, some white and some black, ranging from 6.0 to 11.5 feet wide. The cloth is installed at an angle, so it only partially covers the rows. It’s designed to protect the trees from hail, which usually comes from the west, and shade them in the afternoons.

“Until noon, I have full sunlight on the trees, and then in the afternoon the white shade cloth blocks about 22 percent of the light,” he said. The black cloth, which has a bigger mesh, is supposed to block about the same amount of light, though Robinson said it’s hard to get good numbers for the various cloths.

Karen Lewis, WSU extension educator, said sensors would be put in the orchard this year to assess the actual amount of light interception.

Robinson figures he spent $4,000 per acre on the shades, of which $1,800 was for the fabric. The cost was high because he had to install a new set of 17-foot trellis posts in an existing system. If he were installing it again, he would install the initial trellis with taller posts that also could be used to hold up the shade system.

He also uses evaporating cooling, but said he waits as long as possible during the season, partly to avoid aggravating mildew problems with the moisture and also because he feels it affects fruit finish and results in an unattractive muddy red color. On other varieties, he uses deficit irrigation near harvest to break the background color and hopes to do the same on Honeycrisp.

In blocks that he has without shade cloth, he cools Honeycrisp when the orchard temperature reaches 90°F. When the fruit begin to color, he starts at 85°F. With the shade cloth, he hopes to be able to delay cooling until the temperature reaches 95°F and then use it mostly to avoid heat stress and keep the trees ­growing.

For new Honeycrisp blocks that will go in next year, Robinson will plant nursery trees four feet apart with 11 feet between rows and train them to a single leader. He wouldn’t want rows closer than 11 feet because he plans to use a picking platform and possibly a mechanical ­harvester.

Follow the fruit

Mike Robinson’s orchard at Othello, Washington, is one of three locations on a multistage Honeycrisp Fruit School organized by Washington State University with the Washington State Horticultural Association. The school is designed to allow growers to follow the fruit from early in the growing season through harvest and storage.

The other two orchards are Richard Thomason’s Maverick Orchards in Brewster and Bruce Allen’s Chiawana Orchards in Yakima.

Growers visited the orchards in early June and will return to the same blocks in ­September, near harvest, to see the impacts of orchard practices during the summer and discuss harvest strategies and storage objectives.

Stored fruit will be run over a packing line, and quality and packout data on fruit from the same orchards will be discussed during a full-day Research-to-Practice Workshop on December 5 following the Hort Association’s annual meeting in Wenatchee.

The workshop will cover economics, orchard establishment and site optimization, crop load and light management, harvest strategies, fruit quality, and storage regimes.

“We want people to clearly understand that the production site, harvest strategies, and storage regime all impact the final condition of this apple like no other,” said Karen Lewis, WSU extension specialist. “This is a great chance to get it right and do it together. Prices for Honeycrisp could fall.

If you play Russian roulette on quality with a $3.99-per-pound apple, it’s far different from playing Russian roulette with a 99-cent-a-pound apple.

“The fact that this apple is available for us in Washington to grow is fantastic,” she added. “It’s a big deal. Let’s get it right, and if it means learning from each other to get it right, let’s do it.”

To register for one of the three preharvest tours or the December workshop, contact Joanne Thomas at the Hort Association, joanne@wa hort.org, (509) 665-9641.