Ideal Organic Potato

Spring 2012
Potato variety trials
Blue flags mark rows of variety trials. At far left, ‘Papa Cacho.’ From left to right: ‘Chieftain,’ ‘Peter Wilcox,’ ‘Early Ohio,’ ‘Daisy Gold.’ Photo by Theresa Joseph, NOSP trial grower.

By Sue Smith-Heavenrich

In a country where french fries reign supreme, how does an organic grower find great-tasting potatoes that not only appeal to chefs but also thrive under organic conditions? With more than 60 percent of potatoes headed for processing plants, breeders have found the market slow to accept new varieties – even varieties best adapted to the Northeast, says Walter S. De Jong, professor of plant breeding and genetics at Cornell University.

While he appreciates potatoes with novel coloration – red, purple and yellow-fleshed varieties – the majority of growers, most of whom sell to the french fry and chip market, are looking for starchy, round potatoes.

“Appearance is the number one factor,” De Jong says. “It took me many years to accept that.” 

Still, De Jong focuses his breeding efforts on developing varieties that should, if they taste good, appeal to organic growers. His primary goal is to come up with a potato resistant to the golden nematode (a soilborne pathogen present in New York), but he’s got other goals as well: resistance to common scab, to viruses and late blight; and hairy leaves that make potato plants unappealing to leafhoppers and other insect pests.

The problem, De Jong explains, is getting rid of undesirable traits. He cited ‘Prince Harry’ as an example. Its leaves are covered with tiny hairs that, when touched by an insect, break open and exude a gluey substance. The plant seemed to have everything a grower could want: resistance to leafhoppers, Colorado potato beetles, even flea beetles. It also produced high yields. It had everything going for it except one thing.

Potato Display
Growers participating in the Northeast Organic/Sustainable Potato (NOSP) Project had a wide range of colors and shapes to choose from for their variety trials. Photo by Sue Heavenrich.

“Taste,” says Jim Gerritsen of Wood Prairie Farm in Bridgewater, Maine. Mediocre taste by itself might not have torpedoed the new variety, but back then it had no name. “And you can’t market a variety with just a number on it,” he said.

So Gerritsen suggested calling it ‘Prince Harry,’ and he suggested that breeders keep working to come up with a better potato. They did, and crowned the much improved, tastier offspring ‘King Harry.’

Names are important, says Gerritsen. He believes the agricultural field thinks too industrially. “When it comes to naming, you need to think about what would appeal to the consumer.”

But even the best name can’t sell a potato if the industry continues to promote the image of a “perfect potato” as a generic white round spud.

Gerritsen remembers one Cornell variety he loved: ‘Rosa,’ a white-fleshed tuber with off-white skin and a beautiful rosy blush around the eyes. It tasted good, he said, but suffered from poor marketing. Big potato buyers saw the blush and thought “pinkeye.” They never saw its great qualities, he says. Gerritsen, who likes to highlight unique varieties to his customers, says that ‘Rosa’ was abandoned due to “a remarkable lack of communication.”

Both De Jong and Gerritsen emphasize the amount of time that goes into developing a variety – often three or four decades. While breeders can get a lot of information from growing out varieties on experimental farms, they rely on feedback from a network of potato testers.

Organic potato growers, for their part, are looking for specialty crops that will appeal to consumers with a discriminating palate. At the same time, they need varieties that grow well without synthetic chemical inputs.

Growers compare potatoes
Growers compare notes on their potato varieties during an NOSP workshop. Photo by Sue Heavenrich.

In 2005 Cornell breeders collaborated with the Northeast Organic Farming Association of New York (NOFA-NY) to connect with organic farmers who would trial new varieties and heritage potatoes. Keith Perry, who directs the New York State Foundation Seed Potato Program at Cornell’s Uihlein Farm, provided the seed.

Perry soon discovered that farmers are very good at reporting yields, so after a couple of years the partnership grew into the Northeast Organic/Sustainable Potato (NOSP) Project, with funding from a SARE grant. Elizabeth Dyck served as project grower coordinator through NOFA-NY and, more recently, the Organic Growers’ Research and Information-Sharing Network (OGRIN).

From 2008 to 2010 Dyck worked with more than 100 growers, about half of them home gardeners, to identify potatoes that grow well under organic conditions in the Northeast. Most participants were in New York, but growers in Maine, Vermont, New Hampshire, Pennsylvania and West Virginia also participated. In exchange for seed tubers – growers could choose from close to 50 varieties – they were asked to provide information on their growing conditions, cultural practices and marketing. For example, growers kept notes on how closely they spaced seed tubers in rows, distance between rows, whether they irrigated, when they applied compost and whether they incorporated green manures or used other fertility practices.

Growers also tracked emergence, flowering times, hilling, mulching, weed and insect pests, and diseases, including blight. At the end of each season, they measured yields and rated varieties on criteria including vigor, pest tolerance, taste and consumer reaction.

“Gardeners turned out to be terrific cooperators,” Dyck says. “They often had more time to observe and take notes than commercial growers.” Many participants enthusiastically signed up to continue the trials from year to year.

Although she is still analyzing the data – the final report should be posted to the OGRIN website this spring – Dyck says the data show some clear trends. First, organic yields seem to be lower than mean conventional yields. Depending on the year, organic growers harvested 200 to 250 hundred weight per acre (cwt/A) compared with the national average of around 300 cwt/A.

Some trial participants, however, consistently reported mean yields of 350 cwt/A or more – yields corroborated when project staff visited the farms. Dyck wants to learn more about management practices of high-yielding growers. Those practices, she says, “suggest that high inputs of organic matter during the rotation – manure, compost and green manures – may be a key factor in boosting potato yield.”

NOSP augmented variety trials with field days and grower workshops. Topics focused on cover crops, fertility and developing methods to manage insect pests and diseases. Growers were invited to bring diseased tubers to meetings to share questions and observations. They also gleaned information on reducing the risk of spreading tuber-borne disease when saving potato seed for replanting.

One project goal was to assist growers in starting local “double-certified” (state certified and organically grown) seed potato enterprises. Only one new enterprise began during the project, Dyck says – maybe because organic growers perceive potato seed production as too risky. Still, most growers indicated an interest in participating in a potato seed-sharing network – an idea that got put on hold during the 2009 outbreak of late blight. Despite the setback, Dyck says NOSP staff will continue to work with growers to develop a seed-sharing network, a tuber-buying club, and to help growers achieve certification – if serious interest exists.

De Jong appreciates the feedback he gets from growers, especially the enthusiasm for more diversity in colored spuds.

“There is so much novelty as far as color and shape go,” he says. “White and red potatoes are blasé when we’ve got striped potatoes.” 

People buy vegetables, including potatoes, with their eyes, De Jong says. He believes that the more unusual varieties – the ‘Purple Vikings’ and ‘Adirondack Reds’ – will first find a home in the small farm and organic markets.

“‘Yukon Gold’ had a hard time getting a marketing foothold – even though yellow is the prevalent color of potatoes worldwide,” De Jong points out. That’s because Russets have such a hold on the U.S. potato market.

De Jong would love to see ‘Adirondack’ red and blue potatoes make it into mainstream markets. “I started promoting those varieties about a decade ago,” he says. “But conventional growers rejected them outright.” Now, though, one company is making chips from blue potatoes. Can red chips be far behind?

As for breeding blight-resistant varieties … that depends on how serious the problem becomes. “It’s easy to breed in the resistance, but tubers end up with appearance issues, like cracks and hollow centers,” De Jong says. Nearly every breeding program he knows of has looked at late blight, but it hasn’t become the defining issue for growers yet because commercial fungicides work so well. “If the organic market continues to grow and we have crop failures due to blight, then the incentives may change.”

Growers’ Favorites

A big question for Elizabeth Dyck is whether organic growers actually like any trial varieties enough to grow them for market. After analyzing survey responses, she found that 10 or more growers adopted five favorites:

‘Papa Cacho’ Potatoes
‘Papa Cacho,’ a popular variety among growers, produces foliage that has some resistance to late blight. Photo by Sue Heavenrich.

‘Red Maria’ (formerly NY 129), a red-skinned, white-fleshed potato bred by Cornell. Growers like the color, round shape and uniform size of the tuber. They also like its reliable yield (mean 233 cwt/A) and good taste.

‘Papa Cacho,’ originating in Peru, produces long, skinny tubers. The skin is pink-red, with pinkish to white flesh. Its unique appearance appeals to chefs, and growers note that the foliage is somewhat resistant to late blight. Growers consider its mean yield of 180 cwt/A acceptable for a fingerling.

‘Daisy Gold’ has oval tubers, tan to yellow skin and deep yellow flesh. Growers like its good taste, appearance and yield (mean 243 cwt/A) and say it compares well with ‘Yukon Gold.’

‘Magic Molly’ is an Alaska breed with purple skin and purple flesh that retains its color even after boiling. Many growers adopted it, but some complained of the relatively low yield (169 cwt/A); and its color made tubers hard to spot during harvest.

‘Early Ohio,’ an heirloom variety, has round to oval, slightly flattened tubers. The skin is nearly white, with white flesh that has good taste and texture. Growers like the consistent yield (mean 254 cwt/A) and overall appearance, but some noted that “nice white” potatoes are difficult to sell at market.

Other varieties that growers liked but did not make the top five include ‘Bernadette,’ yellow-skinned oblong tubers with pale yellow flesh and creamy texture; ‘Peter Wilcox,’ a purple-skinned potato with pale yellow flesh and good taste (but disappointingly low yield); and ‘Purple Finger,’ with dark purple skin and deep-purple flesh.

Backyard Potato Breeding

Breeding potatoes is a lot like seed saving, says Bryan Connolly, a botanist for the state of Massachusetts, who, in his free time, grows about 3/4 of an acre of vegetables and, in the past, raised seed for FEDCO. In 2006 he received a SARE grant to “breed colorful and disease resistant potatoes.” He was interested in developing potatoes that would resist leafhopper damage.

Connolly got some ‘Prince Harry’ spuds. “What an awful potato!” he says. It was round, medium-sized and bland-tasting, a totally boring potato with nothing to recommend it except that it set a lot of seed. Connolly crossed ‘Prince Harry’ with other varieties that he did like: ‘Keuka Gold,’ ‘Corolla,’ ‘Purple Peruvian’ and ‘Russian Banana.’ His goal: to produce a potato with a more interesting appearance and better flavor.

Connolly harvested the seed, dried it and planted it the following year. Those first crosses resulted in marble-sized tubers. The most interesting tubers, from the ‘Purple Peruvian’ crosses, yielded both purple and white fingerlings. “They weren’t as hairy as ‘Prince Harry,’” Connolly notes, “but ‘Purple Peruvian’ is fairly leafhopper resistant.” It seems to have some late blight resistance as well, so Connolly believes those crosses may have potential.

He sent some to Jim Gerritsen at Wood Prairie Farm and to FEDCO. He’s curious to see whether anything useful comes of his backyard breeding project. 


The Northeast Organic/Sustainable Potato (NOSP) Project final report will be posted at

“Producing Potatoes Organically in Maine,” Bulletin #2419, a 2006 fact sheet from UMaine Extension;

“Growing Organic Potatoes,” by Vern Grubinger, U. of Vermont Extension;

“2011 Production Guide for Organic Potatoes,” edited by Abby Seaman, Cornell Cooperative Extension;

“Potato Varieties: A Comprehensive List” – descriptions of 625 potato varieties compiled by Washington State University;

“Commercial Potato Production in North America,” by the Potato Production Association of North America – not specifically for organic production, but 90 pages of in-depth information;

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