On a rainy Thursday, July 10, approximately 40 local Delaware growers attended a Small Fruit Educational Tour at the Elbert N. and Ann V. Carvel Research and Education Center in Georgetown to learn best practices on growing blueberries, raspberries, blackberries and grapes in the First State. Among the group, interest in growing certain fruits was evenly divided among each of the small fruit.
Rainy weather changed a planned outside tour into a virtual one – but real live blueberries and blackberries, harvested at their peak, were plentiful for evaluations on taste and appearance. Feedback from growers is an important component to the ongoing research and recommendations UD Extension researchers will make to farmers about which small fruits might be suitable as a commercial crop in Delaware. Additionally, Extension research hopes to offer an expanded growing season with these specialty fruit crop varieties.
Twenty five varieties of blueberries are now being evaluated as part of two ongoing trials, at Carvel REC and Bennett Orchards in Frankford, Del. through a Specialty Crop Block Grant administered through the Delaware Department of Agriculture.
“Blueberries are a challenging crop to grow,” said Gordon Johnson, Extension fruit and vegetable specialist. Johnson said the fruit is native to southern New Jersey and prefers soils in the Pine Barrens region. Growing blueberries in Delaware requires a 2-3 year initial commitment from Delaware growers to recreate the sandy, organic conditions that are native to New Jersey’s soil – soil in which blueberries thrive. To grow blueberries successfully in the First State the following conditions must be met:
- Acidic soil with a pH of 4.5 to 5 pH. “This doesn’t happen overnight,” Johnson said. “It takes a half year to a full year to get it right and it is a grower’s biggest hurdle.”
- High organic soil is needed. Commercial compost is alkaline and should not be used. Planting a cover crop and tilling is helpful, Johnson said.
- Adding soil amendments like pine bark fines helps.
- Peat moss in the planting hole makes a big difference. “This is a must have,” Johnson said. “Otherwise the plant will not take off.”
- Blueberry plant roots do not tolerate heat and must be mulched. Mulch should not raise the pH.
- Drip irrigation. Blueberries require consistently moist soil
Emmalea Ernest, associate scientist for fruit and vegetable crops reviewed second-year results of various blueberry varieties, calling out the names of blueberries in the trial that did well in the Georgetown research farm, and which showed little or no freeze damage, and produced plump, tasty fruit. Legacy was her favorite, Ernest told the audience, with Lenoir and Chandler also showing great potential. But taste preferences are subjective, so Ernest wanted other feedback – important in making final recommendations when the trial is complete.
With clipboards in hand, guests sampled more than 15 varieties of blueberries, identified only by a number. At another table, named varieties were in clear cups so that they could be rated on their size and attractiveness.
The group seemed to concur with Ernest, giving Legacy, Lenoir and Chandler high marks. Two others, Star and Hannah’s Choice also scored praise. A small minority preferred the tart Reka variety. A winning blueberry, however, may not be perfect for all purposes.
“Chandler is really an enormous fruit,” Ernest remarked. “They would be ideal for U-Pick customers. Baskets would fill up quickly,” she said. “But it might be too big for muffins or pancakes.” Chandler is also not a high yielding variety overall.
The meeting also highlighted the Integrated Pest Management (IPM) in small fruit crops. IPM Specialist Joanne Whalen addressed the threat of the Spotted Wing Drosophila, a troublesome fruitfly that Whalen is carefully monitoring throughout Delaware. The small insect lays its eggs inside the fruit which will swell noticeably once infested. “It has the potential to be a really scary bug,” said Whalen. A serious threat in New Jersey, Whalen is curious to know what other growers are seeing and is interested in setting up monitoring projects.
Whalen and her team set up various traps with pheromones, or a cocktail comprised of 40 percent Merlot wine and 60 percent apple cider vinegar to attract any Spotted Wings that might be in the growing area. Whalen said only the males have spots on their wings. Whalen advised the growers to consider removing any wild berries or wild cherry growth from the perimeter of their plots. “Wild pokeberries, wild cherries and even honeysuckle are indicators that Spotted Wing Drosophila could be a problem, Whalen said.
Gordon Johnson also produced yield results data on primocane (fall-season) fruiting blackberries and produced seven varieties for taste and appearance evaluation. Primocane fruiting blackberries offer the potential for extended production for growers, Johnson said, suitable at farmers markets, schools and institution, local restaurants and wholesale outlets. One variety, Ark 45, produced 16,000 pounds per acre (floricane or summer producing) in 2013 with an additional 6,000 pounds per acre on primocanes in the fall, according to handouts shared at the meeting. “The dual production system on both floricanes and primocanes is promising for extended production over an 18-20 week season from June through October,” Johnson writes. Johnson acknowledged that there is “heavy pressure from Spotted Wing Drosophila in 2013 with this extended production.”
For more information visit the University of Delaware’s Small Fruit and Vegetable program website.
Photos and article by Michele Walfred