The first planting of red tart cherry trees in Arizona is now two years old and grower Bob Weaver is cautiously optimistic about his new venture.

Weaver is no stranger to cherry production. Full time, Weaver grows cherries in Leelenau County, Mich., including several hundred acres of conventional- and organic-grown red tart (sour) cherries and sweet cherries.

Michigan is the cherry capital of the world. Red tart cherries, Prunus cerasus, are mostly used in baking and cooking. The sweet cherry, Prunus avium, is mostly consumed fresh.

Weaver’s passion for cherry production led him to consider expansion to other states. Topping his list of options were Washington and Arizona.

Weaver purchased 40 acres near Sunzonia in Cochise County’s Sulphur Springs Valley in southeastern Arizona in 2007. He planted 141 trees per acre in 2009.

“This is a pioneer situation and I like challenges,” Weaver said, taking a break from tractor duties in late May on his farm located near the base of the Chiricahua Mountains. Behind Weaver plumes of smoke rose from the mountaintop from the Horseshoe Two wildfire.

Weaver is settling in as an Arizona red tart cherry grower. Job one, he says, is nurturing the trees to eventually set a uniform crop. Weaver plans to harvest the first cherry crop in 2013.

Weaver acknowledges that Michigan is not Arizona and Arizona is not Michigan as far as growing conditions. He faces a steep learning curve on farming fruit in Arizona’s High Desert. The farm is located at 4,950 feet in elevation.

Several small plantings of sweet cherries in other areas of Cochise County have been largely unsuccessful. One planting was removed due to wind-related limb rub.

“The wind will probably be the top challenge in Arizona,” Weaver said. “I will likely need to install windbreaks to protect the trees.”

For Weaver, fungal disease has not been an issue due to the dry climate but he says powdery mildew could become a problem down the road. The Arizona monsoon rainy season begins around July 15; prime time for fungus spores. Fungal diseases are common on Weaver’s Michigan farm due to higher annual rainfall and humidity.

“My goal is to harvest the Arizona red tart cherries in June before the monsoon arrives and harvest the Michigan cherries in July,” Weaver said.

A bright spot for faster cherry crop maturation in the desert is tied to higher heat units in May and June.

Desert pests can include rodents. Employee Brian Heath showed Weaver a dead, chewed-up tree trunk. Both studied the gnawed wood and concurred the likely culprit was a pocket gopher. The rodent is the only pest problem thus far. As the trees mature, Weaver expects rodent damage will decrease.

Organic production

Weaver’s Arizona farm, Omena Organics, utilizes organic production practices with the exception of glyphosate applications for weed control. Weaver will switch to organic weed measures to qualify for official organic status three years prior to the first harvest.

The trees are the deep tap root-based Montmorency variety on the Mahaleb rootstock. Tree spacing is 14 feet-by-22 feet.

The soil is sandy loam with the top foot acidic and then alkaline further below. About 16 inches under the soil surface is a “gravel pit” which Weaver says increases soil aeration and water flow. The soil pH was 5.4 when Weaver arrived. Added calcium lime has increased the pH level to 6.5.

A soil sample prior to planting revealed ample potassium in the soil, but most was unavailable to the tree. Weaver added K-Mag – a blend of potassium, magnesium, and sulfur – to the soil and takes petiole samples to keep tabs on mineral levels.

The water source is well water pumped from about 600 feet deep which delivers about 50-gallons per minute. This spring, 9 gallons of water per tree per week was delivered by surface drip irrigation. Watering will increase to about 12 gallons per tree a week during the summer.

Weaver is applying Quantum Growth biological products which include high levels of purple photosynthetic bacteria. While low levels of the bacteria are already found in the soil, Weaver says Quantum Growth allows plants to pull nitrogen from the atmosphere for conversion to sugar at a tenfold rate. Another benefit, he says, is improved water retention in the soil.

What are Weaver’s red tart cherry yield expectations?

“That’s the $64 question,” Weaver smiled. “This farm is the first red tart cherry operation in Arizona so there is no history for comparison. I will make history one way or the other through success or failure.”

At tree maturity, Weaver hopes to average about 100 to 110 pounds of fruit per tree – 400,000 to 450,000 pounds for the entire farm. Production will vary depending on the weather. Weaver yields 100 to 140 pounds per tree on his Michigan operation.

Arizona weather a key

“Every crop with a flower is vulnerable to freeze and then you have other weather challenges until the crop is off,” the Michigan native said.

Weather is a key reason why Weaver chose Arizona to grow tart cherries; noting about 850 cold degree hours (below 45 degrees) are required to set a uniform crop.

“You get real winter weather in this part of Cochise County with snow on the ground,” Weaver said. “Daytime temperatures from December into February generally don’t exceed 45 degrees during the day.”

The cherry farm is located near a small grade in the landscape which Weaver believes will protect the trees from frigid spring temperatures.

“The cold nights with no wind can sting you. If you have a grade then the air rolls off – a slow-motion roll. There are no obstacles on the farm to hold the cold. Extreme cold temperatures should roll right through.”

Operating the first red tart cherry farm in Arizona means no nearby processing facilities. Weaver is considering several options.

One is to truck the cherries to Michigan for pitting and processing. Last fall, the Weaver family developed its Omena Organic product line label. The plan includes dried cherries sold in bulk and in 8-ounce bags, plus canned cherries. The family’s label is based on the theme “From Our Farm To Your Table,” www.omenaorganicsfruit.com.

“There is a lot of buzz today emphasizing family involvement in agriculture,” Weaver said. “We are three generations of farmers with our children in the mix. Our product is about our family producing high quality, sustainably-farmed cherry products.”

Another option is to send the fruit to California to process into juice.

Western cherry production includes California where the sweet varieties Bing and Rainier are grown. According to the California Cherry Advisory Board, about 600 farmers grow Bing cherries mostly in the San Joaquin and Santa Clara valleys. Harvest occurs from mid-June to mid-July.

Utah growers produce tart and sweet cherries with about 140 million pounds of sweet cherries grown in 2010.

Michigan, the nation’s top cherry-producing state, produced about 230 million pounds of cherries last year, mostly tart cherries.