Growing Magazine - August, 2013

FEATURES

Edible Nuts

Part of a sustainable Northeast farming system
By Helen Margaret Griffiths


In New Jersey, hazelnut trees flower in mid to late March. Nuts develop in a leafy husk and ripen from mid-August to late September. Nuts remain in or fall from the husk at maturity. These nuts are about two weeks from maturity.
Photo by Thomas Molnar, Rutgers University.

Planting an edible landscape has become popular in recent years. Nut trees have the potential to produce a nutritious crop from land not normally suitable for annual crops, and they need limited chemical inputs. They are particularly suitable for organic growers who want to produce a sustainable food crop. However, whichever tree species is chosen, it is a fairly long-term investment, taking about three years before any nuts are produced, and longer before one realizes a yield of any significance.

Parker Coble was familiar with edible landscapes in the 1950s. Coble grew up on a farm in Adams County, Pa., where his parents were truck farmers. "They were able to pay off the farm with cherry production," said Coble.



Black walnut fruit will be ready for harvest when the hull softens and changes from a solid green to a yellowish color. The harvest period varies depending on the geographic location, but is usually from early fall (late August) until October.
Photo by Thomas Molnar, Rutgers University.

At the time, road transportation to Michigan became much easier, and Coble's father was one of the first to become aware that Pennsylvania was no longer going to be able to compete with Michigan cherry growers. He knew they would have to look at different crops if they were going to make money from their land.

Coble's father started to experiment with grafting nut trees and was successful. In fact, some of the varieties he developed are still champion winners at the Pennsylvania Farm Show. "My father and I worked together to develop nut varieties with improved disease resistance, better taste and larger size. He also taught members of the Pennsylvania Nut Growers Association how to graft," said Coble.



Unlike fruit trees, most nut tree species are pollinated by wind.
Photo by Thomas Molnar, Ru tgers University

A former educator and administrator, Coble has over half a century of experience in the nut business and continues to educate at farm shows, such as the Pennsylvania Farm Show, where he's involved with an edible nut interactive learning station designed to get youth excited about agriculture. Coble hopes to educate enough youth through the exhibit that some choose to follow in his footsteps. "I don't want to take all of my knowledge with me to the grave," he added.

In 1965, Coble started his own venture into edible nut production. "I started it as a hobby with the goal of having something to do when I retired, and it has become a small business," explained Coble, aka the "nutty professor." Coble produces pecans, English walnuts, black walnuts, filberts, shagbark hickory nuts, and his specialty heartnuts (Japanese walnut) and butternuts (white walnut). Nuts have many health benefits. "They are a great source of protein and have omegas, which are good for your heart," said Coble.

Many edible nut tree species are suitable for production in the Northeast. Some have specific requirements, but all require well-drained soil and a site with protection from harsh weather and full sun. "People starting out often buy the $6 seedling rather than pay $30 for the grafted tree, but paying for the grafted tree is by far the best way to go. They yield sooner and grow as you'd expect," he noted.

Coble's Edible Nuts has sold award-winning nuts to every state in the union except Alaska and Hawaii. "I often get residents of New England contacting me for my butternuts, as they remember them from their childhood or have an elderly family member that remembers them. Most of the native trees have now died from the canker, so if people want the nuts they have to purchase them from someone like me," explained Coble.

"This last season, someone came by and purchased $300 [worth] of nuts. Some people have even bought butternuts to make jewelry," Coble noted. With black walnuts being sold for $1.50 per pound, and butternuts and chestnuts going for $3 per pound, $300 buys a lot of nuts. Though some customers purchase on-site, the majority of the nuts he sells are shipped, and he said that shipping costs are becoming an issue. However, the major issues for edible nut growers are disease and wildlife.



Bracing is needed to support the new growth of recently grafted heartnut. A heartnut tree was "topworked" to utilize a tree that had a healthy root system, but did not have good nut cracking attributes. Mature heartnut trees are seen in the background.
Photo courtesy of Grimo Nut Nursery.

Coble has a 3-acre nut orchard at his Gettysburg home, with additional land in Virginia where he evaluates chestnuts, filberts and butternuts. "For the last two years I've had a big problem with bears in Virginia. They don't necessarily kill the tree, but they have a big impact on production. The squirrels have been a problem with the filberts," Coble said.

On the disease side, there's the canker problem with butternuts, as well as bunch disease, particularly in the more southerly regions with heartnut. "I had a terrible time with bunch disease in 2012," Coble said. "Zinc does give some control, but it doesn't fix the problem, and the disease isn't getting that much research attention."

Eastern filbert blight (EFB) is present at Coble's Gettysburg farm, so it can be used as a site for screening for hazelnut cultivars with resistance.

EFB is the main reason why there are no large hazelnut growers currently in the eastern U.S. The majority of hazelnuts produced in North America are in the coastal valleys of Oregon and Washington, where for about 100 years few problems were experienced. However, in the 1960s EFB was found in Washington and eliminated the more susceptible trees, but fortunately didn't decimate all of the plantings.

Dr. Thomas Molnar, assistant professor in the department of plant biology and pathology at Rutgers University, is running several edible nut projects with a focus on breeding for disease resistance, nut quality and ease of cracking. Many nut species have great potential for improvement. Molnar is focusing on hazelnut and black walnut, with a minor focus on heartnut.



Harvesting, washing and drying are important aspects of edible nut production. For washing, a cement mixer can easily be modified to tumble the nuts.
Photo courtesy of Grimo Nut Nursery.

From the hazelnut project, it is likely that within a few years there will be trees of interest for commercial production in the Northeast. Currently there are a number of cultivars that are suitable for home growers in the region, including 'Jefferson' and 'Yamhill'; pollenizers 'Theta', 'Delta' and 'Gamma'; New York state-bred cultivars 'Slate' (NY 616) and 'Geneva' (NY 398); and the Canadian-bred 'Grimo 208P'.

The black walnut tree is native to North America, and its lumber is valuable, but consumers often overlook the nuts. There are hundreds of cultivars available, and some, such as 'Ohio', exhibit good resistance to anthracnose disease.

A thick shell is undesirable from a consumer standpoint, and nut tree breeders have worked to select for cultivars with thin shells, such as 'Sauber'. Molnar and his research staff have been working for over 10 years to identify cultivars that are suited for the Northeast, with disease resistance being high on the list of attributes.

People who plant black walnut should be aware of the eventual size of the tree and be sure to provide enough space. Coble says, "I interplant peaches with black walnut, as the peach tree is relatively short-lived, so by the time the black walnut needs the space, the peach tree is finished."

Anyone who wants to grow black walnut should also know that they produce the toxic compound juglone, which is allelopathic to many other plants and can sicken or kill animals.

Heartnut has advantages over the other walnut species, not the least of which is its resistance to walnut anthracnose and walnut blight. They are fast-growing trees, and grafted trees produce nuts in the second year and continue growing to be prolific producers. They also grow to be big trees. "I have a 30-year-old heartnut tree that from the trunk has an 80-foot wingspread, and it is not fully grown," said Coble.

Nut harvesting is similar to other walnuts, but the cracking needs some study, and there needs to be some marketing, as few people are familiar with the nut and flavor. The ideal heartnut opens like a locket. Coble and Ernie Grimo, from Grimo Nut Nursery, Niagara-on-the-Lake, Ont., work together on evaluating each other's cultivars. "Ernie is a good collaborator," said Coble, who has great faith in the future of heartnut for the region. "One of these days, the heartnut will come alive," he said.

The author is an agricultural freelance writer and plant pathologist who lives in the Finger Lakes region of New York.

For Further Information

Research

For information on Dr. Thomas Molnar's research and the availability of the new hazelnut cultivars, visit http://aesop.rutgers.edu/~plantbiopath/faculty/molnar/molnar.html or contact him directly at molnar@aesop.rutgers.edu.

Grafted nut tree suppliers

Grimo Nut Nursery: http://www.grimonut.com

Coble's Edible Nuts: 717-334-6876

Associations

New York Nut Growers Assoc.: http://www.nynga.org

Northern Nut Growers Assoc.: http://www.nutgrowing.org

Pennsylvania Nut Growers Assoc.: http://www.pnga.net