Jicama Thai seeds to plant in your Garden at home. Thai Jicama is a Asain Variety of Jicama. Jicama is a crispy, flavorful root vegetable with a vigorously growing vine that easily reaches up to 20 feet in length. It is unfussy to grow but requires nine months of warm weather before harvest. In cooler climates, it should be started from seed indoors in the late winter. Only the flesh of the tuberous root is edible. Do not eat the leaves or stalks. When to plant your seeds? Jicama requires a long growing season. Unless you are located in the warmest parts of the United States, Puerto Rico, Hawaii, or the Southwest, it's best to start seeds early in the year. Jicama plants can be direct-seeded outside in USDA hardiness zones 10 through 12, but if your region experiences frost, the seeds should be started indoors 8 to 10 weeks before the last spring frost. Like potatoes, jicama grows in rows. Plant tubers 5 inches deep, spaced 2 feet apart in rows 5 feet apart. If transplanting seedlings, space them 12 inches apart. If you want to keep the plants off the ground, they will require support at some point. You can train jicama on a net, wire fence, or bamboo tripod, but remember that if it is raised off the ground, it might be more difficult to protect it from frost. The plant thrives in full sun. This species is a day-length sensitive plant, meaning the tubers are not produced until the days are shorter than nine hours toward the end of the growing season. Soil Jicama grows best in well-drained soil that is loamy and sandy with a pH between 6.5 and 8.0. Heavy, wet soils are not suitable. While it does not tolerate soggy soil, jicama requires consistent watering. The soil should never dry out. Water the plant at the soil line rather than on the leaves. Ensure your jicama plants receive at least 2 inches of water per week to mature and produce healthy tubers. Temperature and Humidity Jicama plants are susceptible to frost and don't tolerate temperatures below 50 degrees F. The plants thrive in hot weather with average to high humidity levels.