(Yam Bean, Mexican Turnip)
Dr. Joe Masabni
Department of Horticulture
Texas AgriLife Extension Service
Jicama, a legume, is grown for the large tuberous roots which are eaten raw or cooked and are used as a source of starch. The jicama plant is a vine which grows to a length of 20 feet or more. Roots are light brown and may weigh up to 50 pounds. Most of those on the market weigh 3 to 5 pounds.
Jicamas are actually perennials and produce their large roots after several years of growth. They are commonly found in frost-free regions. In Texas, plant seed in the early spring and harvest small tubers before the first killing frost. The root or tuber initiation and development are dependent on photoperiod or length of day. Plants exposed to relatively long days of 14 to 15 hours do not produce tubers. Areas with mild fall or winter temperatures are best suited for yam bean production.
Jicamas are suitable for consumption at any growth stage (size). Look for well formed tubers that appear fresh and are free of cracks and bruises. Jicamas, like most other root crops, store for relatively long periods in refrigeration. However, conversion of starch to sugar occurs if stored for excessive periods and should be avoided.