Jicama is a tropical legume, scientifically known as Pachyrhizus erosus, cultivated for its large, edible, starchy root. This root vegetable, often called a yam bean or Mexican turnip, has a crisp texture and a mildly sweet, nutty flavor, making it popular in many cuisines. The plant is a vigorous vine requiring specific environmental conditions and a long growing cycle to produce the marketable tuber. Understanding these needs is fundamental to a successful harvest.
Climate and Soil Needs
Jicama requires a long, warm growing season, needing 150 to 200 frost-free days to fully mature the roots. It thrives in tropical and subtropical conditions where temperatures remain consistently high. Temperatures below 50°F (10°C) can damage the vines, and frost will immediately end the growing season.
The location must provide full sun exposure for at least six to ten hours daily. Jicama grows best in loose, well-drained soil, preferably a sandy loam that allows the root to expand easily. Heavy or waterlogged clay soils are unsuitable because they can cause the roots to rot or become misshapen.
An optimal soil pH range is between 6.5 and 8.0. Before planting, incorporate organic matter, such as aged compost, to enrich the soil and ensure good drainage. As a legume, jicama fixes its own nitrogen, meaning additional nitrogen fertilizers are unnecessary once the plant is established.
Starting the Plant and Initial Growth
Because jicama requires an extended growing period, gardeners in regions with shorter summers often start seeds indoors six to ten weeks before the last expected spring frost. To improve germination, the hard seed coat should be lightly nicked or sanded, then soaked in water for 12 to 24 hours before planting.
Seeds should be planted one-half to one inch deep in a warm soil medium, ideally maintained between 75°F and 90°F (24°C and 32°C). Seedlings are ready for transplanting outdoors only after the danger of frost has passed and the soil has warmed. Once transplanted, seedlings should be spaced approximately 12 inches apart.
The initial growth phase involves the rapid development of vining foliage, which quickly begins to sprawl. Young plants require consistent moisture, but not overly saturated soil, to support this burst of growth. This early vegetative growth sets the stage for the underground tuber formation.
Mid-Season Care and Harvesting
Once the jicama vine begins its vigorous mid-season growth, specialized care is required to direct the plant’s energy toward root development. The vines can easily reach lengths of 15 to 20 feet, making a strong support structure or trellis necessary to keep the foliage off the ground. Providing this support also helps ensure adequate air circulation, which is important for plant health.
A specialized step in jicama cultivation is the removal of flowers and any developing seed pods as soon as they appear. Allowing the plant to flower and set seed will divert significant energy away from the underground tuber. Pinching or pruning these blooms redirects the plant’s resources, causing the root to swell and maximize the edible yield.
Harvesting typically occurs six to nine months after planting. A common visual cue for maturity is the yellowing of the vine’s foliage, which signals that the roots are fully formed. The roots should be carefully dug up using a garden fork to avoid damaging the skin, as blemishes can reduce the storage life. Jicama roots are best harvested before the first hard frost, as they do not tolerate cold temperatures.