Journal of the NACAA
Volume 4, Issue 1 - June, 2011
Still in the Game: Late-Planting And Cool Temperatures Doesn't Mean A Poor Potato Crop
- Smeenk, J., Extension Specialist of Horticulture, University of Alaska Fairbanks Cooperative Extension Service
Martin, S.V., Horticulturist, University of Alaska Fairbanks Agricultural and Forestry Experiment Station
Many agricultural regions throughout the country face issues such as a shortened growing season due to late planting and decreased crop performance due to cool temperatures during the growing season. Alaska’s agricultural producers and home gardeners face these issues constantly, as the growing season is characterized as being both short and cool. A potato variety demonstration trial at the University of Alaska Fairbank's Matanuska Experiment Farm in Palmer, Alaska has resulted in useful information regarding potato varieties that produce well despite the challenges of Alaska’s growing conditions. The presented data from this trial may be beneficial to individuals throughout the country who face similar growing season challenges.
There are many factors that can cause late-planting dates for home gardeners, and planting at later dates ultimately decreases the overall length of the growing season for those individuals. Furthermore, many locations experience unpredictable weather patterns, which can often bring unexpected cool temperatures during the summer months. Despite these challenges that individuals may face, all is not lost. One crop that can still make a late-planted garden or an unexpected cool summer produce expected food is potatoes. While many of the varieties that are familiar to gardeners throughout the country do well under normal conditions, the shortened season created by planting late and often abnormally cool temperatures can hinder the development of these varieties, making them a poor choice for these situations. Therefore, documented performance of different varieties that do well in Alaska’s cool, short growing season may be very beneficial when deciding which varieties to plant.
Potatoes are Alaska’s largest vegetable crop, with production sites located throughout the state. At the Matanuska Experiment Farm in Palmer, Alaska, new and heirloom potato varieties are evaluated for performance and quality under Alaska’s growing conditions. As part of this evaluation process, many varieties are grown in an ongoing Demonstration Trial, which is meant to introduce farmers and home gardeners to new varieties, and provides examples of many heirloom varieties for potato growers in the state who are looking to expand their potato production repertoire. The majority of the potato seed is provided by the Division of Agriculture’s PlantMaterialsCenterpotato program, while other varieties are acquired from certified seed vendors outside of Alaska. Not all varieties are readily available every year, so the reported data indicates the number of years each variety was observed.
South Central Alaska’s growing season is short in comparison to most other potato-producing regions throughout the country. The ground thaws enough for planting between mid-May and early-June, and harvest occurs in early to mid September in order to avoid frost damage. In addition to the short growing season, the daily high temperature in Palmer may exceed 70°F less than ten days per year, providing fewer heat units to the plants than in other locations.
The planting sites are chisel plowed, then rotor-tilled, and furrows are opened with a potato planter that also bands 10-20-20 fertilizer at a rate of 1,200 lbs/A. Seed is either selected as a 1.5-2.5 oz whole tuber, or larger tubers are cut into similarly sized pieces. Seed is hand-planted at 11” in-row spacing, with 3’ between rows, and covered with 3”-5” of soil using closing disks. The rows are hilled later in the growing season when the majority of the plants are 8”-14” tall. Although natural rainfall averages 16” per year, the potatoes are irrigated to avoid drought stress. All potatoes are machine harvested in early to mid-September.
Evaluation is primarily based on industry standards for US#1 and US#2 potatoes. The potatoes are dumped onto a sizing chain which removes the “small” potatoes, which are those less than 2” in diameter. “Defect” and “oversized” potatoes are removed by hand, and the remaining tubers are “marketable,” meaning they would commercially pass for either US#1 or US#2 potatoes. Many potatoes that are selected as “defects” could easily be made edible for a home gardener by removing the skin prior to cooking, removing green or other unwanted parts, or by simply ignoring their abnormal shape. Likewise, home gardeners can also enjoy eating the “oversized” potatoes, as their only flaw tends to be their size and in some cases, their abnormal shape.
Locating the varieties:
Some of the reported varieties are easy to find locally as certified seed, while others may require more effort to locate. A general Internet search should provide a list of vendors for most of the varieties reported. Furthermore, rare varieties may need to be acquired as tissue culture plantlets or as tissue culture micro-tubers from a potato tissue culture repository.
The presented results are grouped in large categories based on skin color, flesh color, and/or shape. The following websites may prove useful for more complete variety descriptions and many include photographs.
Washington State University potato variety list, from the WSU Research and Extension Service. http://potatoes.wsu.edu/varieties/vars-all.htm
European Cultivated Potato Database, includes many non-European varieties as well. http://www.europotato.org/menu.php
Helpful site for the home gardener, includes information on potato varieties as well as other crops. http://davesgarden.com/
Irrigated Potato Trial
Matanuska Experiment Farm (Palmer, Alaska)