Pests & Diseases
Like other root vegetables, jicama is susceptible to bacterial spot and various fungal diseases, especially if soil is too moist.
Few pests are interested in jicama plants due to the natural toxicity of its above-ground parts (vines, stems, flowers, and pods), which are infused with the toxin rotenone. Weevils and borers, however, have been known to attack developing roots.
Jicama grows best in sunny, temperate climates and is sensitive to frost. Seeds, which resemble those of beans, should be planted in well-drained loamy soil, in wide rows with plenty of space (at least several feet) for jicama’s sprawling vines (up to 20 feet) to thrive.
Once planted, jicama grows as a sturdy, fast-spreading vine above ground, with a slowly developing taproot in the soil. Highest quality, fleshy roots will grow better with ample sunshine and warmer temperatures.
As the root fills out underground, plentiful white or blue-purple flowers will bloom and bean-type pods will become visible above ground.
Flowers should be culled early for better root development. Growth, however, is very slow and takes months, though this is dependent on day-length (short-day varieties are most prevalent) and temperature range.
Blossoms and pods are sometimes targeted by pests, but rotenone keeps most predators at bay (though immature pods are said to be far less toxic than mature pods). Care should be taken to consume only the white flesh of the tuber, after cutting away the rough, fibrous skin.
Jicama is harvested from 3 to 6 months after planting, sometimes longer, with the rounded root weighing from 3 to 6 pounds. If left in the ground, jicama will continue to grow in both size and weight (upwards of 20 to 40 pounds), though it will lack the plant’s characteristic sweetness and become more starchy.
Tubers should be firm, free of cuts or abrasions, cracks, or discoloration. Jicama should be stored in a cool, dry space with humidity of 65 to 70% to prevent moisture and flavor loss.
Storage & Packaging
Roots can last for several weeks under cool, dry conditions with temperatures ranging from 54 to 65°F and 65 to 70% humidity. Too much moisture encourages the growth of mold; if temperatures are too cool, chilling injury will result in both external and internal damage including decay and discoloration (the colder the temperature, the more severe the damage).
After peeling and slicing, jicama will not turn brown from oxidation. It can be stored in the refrigerator for a week if wrapped in plastic.
References: Cornell University, Texas A&M AgriLlife Extension, University of California Agriculture & Natural Resources, University of California Cooperative Extension, University of Hawaii at Manoa, USDA.
GRADES & GOOD ARRIVAL
Currently, there is no grade information or good arrival guidelines specific to jicama for the United States or Canada.