A Detailed Guide to Growing Yacon: Is the Southern Region Suitable for Planting?

Yacon is also known as yacon potato, crystal potato, chrysanthemum potato, divine fruit, ground ginseng fruit, etc. It is a perennial herbaceous plant of the genus Smallanthus in the Asteraceae family. Its tuberous roots are rich in water and fructooligosaccharides, taste both sweet and crisp, and can also be eaten as a fruit. In recent years it has been planted in many places, so what is the growing method for yacon? Can the southern region adapt to its growing conditions?

1. Can the southern region of our country adapt to its growing conditions?

1. Yacon can be grown in the southern part of our country.

2. Yacon is particularly suited to growing on sandy soil at an altitude of 1000-2300 m. It likes sunlight and moist soil. Its growing period is about 200 days or more, and its optimum growing temperature is 20-30°C. Below 15°C growth stops, it is not cold-tolerant, and its stems die when exposed to frost.

3. Distribution of yacon: it originated in the Andes Mountains of South America, and is grown in Peru, Argentina, Yunnan in China, Taiwan, China, and other places. It has been successfully introduced and cultivated in Yunnan, Fujian, Hainan, Guizhou, Hunan, Hubei, Shandong, Henan and Hebei.

2. What is the growing method for yacon?

1. Seed selection: when planting yacon, good seed tubers or seedlings should be purchased. The seed tubers are required to have plump, intact buds and a reddish color, and the seedlings should be glossy green and robust, free of disease and damage.

2. Planting time: yacon is best planted after the seed tubers are cut, leaving 3-4 buds on each cut tuber. Direct sowing should be done before April 15. Sowing with plastic film mulch is best done at the end of March, and if conditions allow the building of small arched sheds, the time can be moved even earlier. Raising seedlings in nutrient pots should be done in early to mid-March, and after the frost-free period they are transplanted to the field and watered promptly. The earlier the planting, the higher the yield. Yacon planted in May-June shows a clear drop in yield.

3. Land preparation and ridging: choose sandy loam with convenient drainage and irrigation, and avoid low-lying sandy loam. Open furrows at a row spacing of 0.8-1 m, and evenly apply 2000 kg of fully decomposed human, livestock and poultry manure and 20 kg of compound fertilizer per mu in one application. Then form ridges (also called forming beds), and later earth up and raise them during cultivation, the purpose being to increase the daily soil temperature difference and promote fruit enlargement.

4. Raising seedlings and transplanting: in late February, after the root buds sprout, cut the root buds apart, with 1-2 buds per piece, coat the wounds with plant ash and then bag them for seedling raising, water thoroughly and cover with film, and remove the film once roots grow and seedlings emerge. During the seedling stage, do not water too much; just keep the soil moist. In late March and early April, when the seedlings have grown to about 10 cm tall, they can be transplanted, and at transplanting time water thoroughly to settle the roots. Direct sowing in the field can also be used.

5. Planting density: 1000-1200 plants per mu, with a plant spacing of 0.6 m and a row spacing of 1 m, planting in a staggered pattern between rows. You can first plow and then ridge and plant according to the specifications, or dig planting pits for planting. The planting pits measure 50 cm × 50 cm and are 40 cm deep. After backfilling 30 cm of soil, apply 3-5 kg of decomposed farm manure per pit and 0.15 kg of high-quality compound fertilizer per pit, mix thoroughly with the upper layer of soil, and then plant the seedlings in the pit.

6. Mid-season management: after transplanting yacon, water promptly to ensure the survival rate. Once the rainy season arrives, dig drainage ditches well and do not let the plants be submerged or waterlogged. Do a good job of cultivation and weeding, earthing up and ridging while weeding. In principle, no chemical fertilizers or pesticides are applied throughout the growing period; weak seedlings can be watered with clear manure water or biogas slurry. In July and August, the plants enter the vigorous growth period, the branches grow wildly, and for those with too many branches, pruning should be combined with earthing up, removing overly dense branches, pruning deeply in the early stage, and only pinching the tops in the later stage, to control excessive aboveground growth and retain about 10-12 robust branches.

7. Late-stage management: yacon enters the flowering period in September, with five yellow sunflower-like flowers opening on each branch. After the flowers fade, it enters the maturity period, and once the flowers on all branches have faded, it can be harvested gradually.

8. Timely digging: the sign that the underground fruit of yacon is mature is the withering of the small clustered yellow flowers that open at the stem tips around October, at which point it can be dug. It should be dug before freezing and stored indoors or in a cellar. It can be stored like sweet potato, and the stems can be used as high-quality feed. The leaves and flowers, like the fruit, have high nutritional value and can be dried for tea or sold. With about 1000 plants per mu, a single plant generally yields about 3 kg, and the highest single-plant yield can reach 10 kg.

9. Seed preservation: after digging yacon, cut off the upper seed part of the fruit, dry the wounds, soak them in a 75% potassium permanganate solution for 2 minutes, take them out with the buds facing up, and store them in moist sand in a cool place for temporary planting. When the sand is dug open the next February and the seed buds have grown to about 4 cm, they can be planted out (each place should decide according to local temperatures).