How to Grow Yacon? A Detailed Guide to the Latest Methods
Yacon (Smallanthus sonchifolius) is a perennial herbaceous plant in the genus Smallanthus of the Asteraceae family, native to the Andes Mountains of South America. It is a traditional root-tuber food of the local Indigenous peoples; the residents of the Andes grow this plant as a root vegetable and also eat it as a fruit. It was introduced to China in 2008 and first began to be cultivated in Yunnan Province. Now let us take a look at how to grow yacon!
Yacon Growing Conditions
Yacon has been successfully introduced and cultivated in Yunnan, Fujian, Hainan, Guizhou, Hunan, Hubei, Shandong, Henan and Hebei, and is especially suited to growing on sandy soil at altitudes between 1000 and 2300 m. It likes sunlight and moist soil, and requires terraced land, terraced fields or gentle slopes that have irrigation water but will not be flooded. The growing period is about 200 days, and the optimum growing temperature is 20-30°C. Growth stalls below 15°C. It is not cold-tolerant, and the stems die when frost occurs.
Yacon Seedling Raising Techniques
1. Seed selection: When growing yacon, choose good seed tubers or seedlings. The seed tubers should have plump, intact buds and a reddish color, and the seedlings should be glossy green, robust, disease-free and undamaged.
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 small arched sheds can be built, it can be done even earlier. Raising seedlings in nutrient pots should be carried out in early to mid-March, then transplanted to the field after the frost-free period and watered promptly. The earlier it is planted, the higher the yield; yacon planted in May to 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 plus 20 kg of compound fertilizer per mu in one application. Then form ridges (also called making beds). Later, during cultivation, earth up again to raise the ridges. The purpose is to increase the daily temperature difference of the soil and promote fruit enlargement.
Yacon Growing Techniques
1. 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, then bag them for seedling raising. Water thoroughly and cover with film, and remove the film once roots grow and seedlings emerge. Do not water too much during the seedling stage; just keep the soil moist. In late March to early April, when the seedlings have grown to about 10 cm tall, they can be transplanted, and water thoroughly at transplanting to settle the roots. Direct sowing in the field can also be used.
2. 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 holes for planting. The planting holes should measure 50 cm × 50 cm and be 40 cm deep. After backfilling 30 cm of soil, apply 3-5 kg of decomposed farmyard manure per hole and 0.15 kg of high-quality compound fertilizer per hole, mix well with the upper soil, and then set the seedlings in the holes.
3. Mid-season management: Water promptly after transplanting yacon to ensure the survival rate. Once the rainy season arrives, dig drainage ditches well; do not let the plants be submerged or waterlogged. Carry out cultivation and weeding well, and earth up to form ridges 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 stage, and the branches grow wildly. For plants with too many branches, prune and trim them along with earthing up, removing overly dense branches. Prune deeply early on, and only pinch the tips later, to control excessive aboveground growth and retain about 10-12 robust branches.
4. Late-stage management: Yacon enters the flowering stage in September, with each branch bearing five yellow sunflower-like flowers. After the flowers fade, it enters the maturity stage, and once the flowers on all branches have faded, it can be harvested gradually.
5. Timely harvesting: The sign that the underground fruits of yacon are mature is the withering of the small clustered yellow flowers at the stem tips around October, at which point they can be dug up. They should be dug up before freezing and stored indoors or in cellars. They can be stored like sweet potatoes, and the stems can be used as high-quality feed. The leaves, flowers and fruits all have high nutritional value and can be dried for tea or sold. About 1000 plants are planted per mu, generally yielding about 3 kg per plant, with the highest single-plant yield reaching 10 kg.
6. Seed-saving technique: After harvesting yacon, cut off the upper part of the fruit used as seed, 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. In February of the second year, when the seed buds have grown to about 4 cm after uncovering the sand, they can be planted out (the timing should be determined according to local temperatures).