A simple mock-up shows the idea behind the over-the-row platfom that is being developed. 

A simple mock-up shows the idea behind the over-the-row platfom that is being developed. 

A team of research and Extension people in the Pacific Northwest is working on a big idea—an over-the-row contraption that will carry workers on suspended platforms through an orchard five or seven rows at a time, depending on the row spacing.

It will be propelled by a tractor with booms going over the tops of two or three rows on each side, spanning 50 or 60 feet. The booms will be high enough to clear a 12-foot-high tree canopy. The platforms, which will be about five to six feet long, will be suspended from the booms. Each will carry one or two workers, who could be doing a variety of orchard jobs, from pruning or tree training to thinning or picking.

When picking, workers will place fruit on a conveyor belt that will go over the tree rows and deposit all the fruit at one end of the device in a wider alley, where there will be bin fillers and trucks to receive the fruit.


A prototype of the platform is being fabricated by Jack Maljaars with Vine Tech Equipment in Prosser, Washington, and should be ready for testing before this year’s Gala harvest.

Dr. Dana Faubion, Washington State University Extension educator in Wenatchee, who heads the development team, said the idea of suspending workers on platforms, instead of having them climb ladders, came from growers.

“I’ve thought about this for years,” said Bruce Allen, a Yakima area grower and shipper, although his idea was to go across 200 to 300 feet of orchard at a time.

Other growers Allen talked to, including Jerry Haak and Mario Martinez, also thought the over-the-row concept made more sense than ladders or single-row platforms.

The tree fruit industry has had some success using mechanical platforms that travel down one row at a time on wheels, but Allen said if they carry only four to six pickers, some of the larger orchard operations could need anywhere from 20 to 50 platforms to get their crops harvested, which would not be economically feasible.

The only way to progress to covering multiple rows at a time is to develop an over-the-row device. “It gives you an opportunity to more effectively mechanize the harvesting operation,” Allen said, noting that for most growers labor represents 50 percent of their operating costs—assuming that labor is available.


The Washington Tree Fruit Research Commission is investing close to $150,000 in developing the device, the largest amount it has ever granted to a single project.

Faubion said there are no guarantees it will work. “It’s fairly risky. It’s out there. But I think it’s an acknowledgement by the commission that labor continues to be a huge issue.

“With our current labor issues, I think it’s justified. There’s an acknowledgement that our management needs to be a little more sophisticated than just giving a guy a pruning lopper and a ladder.”

“This industry is looking for all the options and opportunities to stabilize our workforce,” commented Karen Lewis, WSU Extension educator in the Columbia Basin. “That doesn’t mean we just want to reduce the numbers. What we need to do is employ fewer numbers of people for longer periods of time. We would reduce the number of people required to get a given task done. We do that because we increase the efficiency and the speed at which the task is done.”


The development team is tackling the project from a number of angles.

Nagarajan Ramalingam, research assistant at Oregon State University in Hood River, has been looking at the engineering feasibility with computer modeling. Faubion said it appears that the device will be able to turn quite easily at the ends of the rows, because it will telescope.

“The concept seems to negotiate the end row really easily,” he said. “We’re not too worried about that. But slope is a real concern, and there are a lot of safety issues.”

Faubion said it’s possible the device could be used without workers for spraying. If, as a sprayer, it could travel at three miles per hour, covering seven rows at a time, a driver could cover 130 acres in a seven-hour shift. “The efficiency gained, it’s pretty phenomenal,” he said. “But there are drawbacks as well. We’re trying to engineer our way out of those as much as possible.”


OSU economist Dr. Clark Seavert is looking at the economic feasibility. Using his TEAM (Technologies Economic Assessment Model), Seavert calculates a potential 30 percent reduction in labor costs for pruning, tree training, and thinning, assuming that the efficiencies of a single-row platform can be duplicated in the multirow platform. With that 30 percent savings, a typical orchardist could afford to spend $100,000 on the platform, he figures. Any additional savings from other jobs, such as spraying or harvest, would mean more money in the grower’s pocket. He figures one machine could probably cover 100 acres.

Allen believes that despite the relatively high initial investment, growers will end up spending less overall on machinery and equipment, especially if the multirow platform can be used for multiple orchard tasks, such as spraying or mowing. A single tractor nowadays can cost more than $30,000.

“I think this has the potential to significantly reduce our costs,” Allen said. “I would be shocked if you couldn’t reduce your costs by 50 to 60 percent for almost every activity we do. Long term, it might lead to better fruit quality, because it might allow growers to do things they don’t have time to do now.”

He envisions that it could be fitted with sensors for site-specific irrigation, fertility, or spray applications.

Seavert said if the device allows growers to do a better job in the field, that should translate to increased income, as well as lower costs.

“I feel that because of these platforms, we’re going to do a better job of pruning and thinning, and I think we’re going to affect fruit size and quality. Once you affect packouts, that’s where you make the biggest impact on your return on investment. Anytime we start shifting the revenue curve up, it’s just a tremendous advantage. I think that’s what platforms are going to do for the industry in remaining competitive.”

Having a large volume of fruit accumulated in one location in the orchard, at the end of the belt, would make it more feasible to presort the fruit to remove culls before it goes into the bin, in order to optimize returns.

Tom Auvil, research horticulturist with the Research Commission, said packers are charging growers between $50 and $150 a bin in fixed costs on fruit that growers bring in.

Initially, sorting will be done by hand, but the ultimate goal is to incorporate a fruit handling system with electronic sorter to grade and presize the fruit and eliminate culls.

Faubion said the economic advantages of reducing cullage, and thus warehouse in-charges, make this an essential part of the system. “Just by getting rid of 10 percent of the culls and 20 percent of the peelers, and hauling them straight to Tree Top or whoever, then these economics start to make even more sense. Even in high-quality blocks, culls kill you,” he said. “Getting rid of those is a huge economic gain.”

In addition, Allen said the savings from not having to transport bins out into the orchard rows and bring them back to load on a truck to go to the warehouse would be substantial. He estimates that it currently costs $2.50 to $3.00 a bin to move bins around the orchard during harvest.

“If you were doing multiple rows and you didn’t have to take the bins out into the orchard, I could envision where you could easily cut that cost in half and eliminate probably 30 percent of the tractor requirements.”

A major drawback of mechanical apple harvesting systems that have already been developed is the tendency for fruit to be bruised as it goes into the bin.

Mechanical engineer Malcolm Hanks with Hardco LLC in Yakima, has designed a new type of dry bin filler that employs robotics to gently deposit fruit in the bottom of the bin. The bin filler, developed with the support of a U.S. Department of Agriculture grant, will
be tested in the field this summer, along with the prototype of the multirow platform.


Allen said many existing orchards don’t lend themselves to the multirow platform and to take advantage of it, growers will either need to replant or retrain their trees.

Auvil is developing a three-acre test block of Gala apples at an Allan Brothers orchard in Prosser to figure out what type of orchard system might best suit the multirow platform. The trees will be planted next spring, some on dwarfing Geneva rootstocks. “We’re just trying to determine horticulturally what we could do on tree height and spacing,” he said, “And the next step would be to look at the progress we’re making in the development of the over-the-row system and see what’s going to make the most
sense between what we know horticulturally and what we’ve learned from the mechanical side.”

With the multirow platform, alleys won’t need to accommodate bins and tractors so the tree rows could be closer together. In the trial, rows will be planted four, six, and eight feet apart, with three to four feet between trees. A formal training system with precise positioning of tree limbs on a thin, flat plane could ensure enough light throughout the trees even when the rows are so closely spaced, Auvil believes. He’ll probably use a training system based on the extremely productive system used at Auvil Fruit Company in Vantage. He’ll try both vertical and angled trellises and will look at the economic impacts of the considerable investment in labor that is required for positioning the limbs and tying them to the trellis.

He’ll try using drip irrigation and the growth regulator Apogee (prohexadione calcium) to control vegetative growth, and will try using a reflective mulch to optimize light distribution in the trees. He aims to have the canopy grown within two seasons and a crop in years three and four.

Dave Allan, a partner at Allan Brothers, said that currently the bin is the limiting factor in row spacing. He has been planting rows 8.5 feet wide, which is about as close as they can be to allow access for a four-foot-wide bin and tractor, with two feet on either side. Spraying such narrow plantings on hillsides is difficult because of the leaning of the tractor.

“By taking the bin and the tractor out of the equation, and going over the row, it opens up possibilities,” he said.

One is that if rows could be planted closer, trees could be kept shorter—say 8 or 8.5 feet tall—without sacrificing overall yield, and then most jobs could be done from the ground or a small step-stool. It might even be possible to eliminate the platform for some jobs, although at harvest there would have to be some way to elevate the fruit and move it to a drive row to be put in the bin.

When workers use 10- or 12-foot ladders, they’re working about 7.5 feet above the ground, and there’s the risk of falling. Ladders are also extremely inefficient, Allan noted. The worker climbs up and works from a small area at the top of the ladder and then has to climb back down again to move it.

“The ladder is the enemy,” he said.