As Chinese potatoes mostly depend on monsoon, this is the ideal time to start cultivating the tuber crop. Though smaller in size, the unique taste and aroma makes Chinese potato equally popular with tapioca. In Kerala, the crop is grown in harvested paddy fields and low-lying lands. It is commonly found in Thrissur, Palakkad and Malappuram districts.
Planting
Chinese potatoes grow well in soil mixed with sand. Mature tubers weighing 15-20 grams are planted in the nursery at a distance of half a foot. After 3 weeks, 10-15 centimetres long tender stems are cut and replanted in the farmland. The small round-shaped Chinese potato bought from shops can be used for growing the sprouts.
The farmland has to be tilled well before planting. Add lime in soil in a ratio of 1 kilogram per 1 cent. After a week, add cow dung in a ratio of 40 kilogram per 1 cent. Then make flowerbeds with a height of 1 foot maintaining a distance of 1.5 foot.
Fertilizer
Chemical fertilizer is commonly used in farming on a commercial scale. Urea, potash and rajphos are used in chemical methods. In organic method, ash can be used as base and top fertilizer replacing potash.
After 4-5 months of planting, the leaves turn yellow and the edges of the plant starts getting dried. This indicates harvest time. Chinese potato seeds can be preserved in a place with proper ventilation by covering with soil in 1 inch thickness.
Best varieties
'Sreedhara' developed by the Central Tuber Crops Research Institute in Sreekaryam in Thiruvananthapuram is a good variety of Chinese potato. It can be harvested in 150 days.
Nidhi and Saphala varieties of the Kerala Agricultural University also are good choices. Their harvest period is around 120-135/140 days.
Pest menace
Normally, Chinese potatoes are not attacked by any pests. But nima worms in the soils distort the tubers sometimes. Till farmland before summer and add neem cake in soil to prevent them.
Some farmers also opine that intercropping a sweet potato variety named 'Sreebhadra' helps reduce the menace of nima worms.