Konjac (Amorphophallus konjac) is not an established crop in India. No Indian variety, package of practices or organised buyer for konjac corms was found, and most of the world's supply comes from China, Japan and Southeast Asia. Planting it as a commercial crop today means doing a trial on your own risk, ideally only with a processor or research institute that has agreed in writing to take the corms.

The crop that Indian farmers do grow commercially in this genus is elephant foot yam (Amorphophallus paeoniifolius), which is a vegetable, not a glucomannan source. Do not use elephant foot yam prices or yields for konjac. See elephant foot yam if a proven Indian tuber crop is what you need.

What is documented about the crop

  • Species: the genus has about 200 species, and only two are commercially cultivated worldwide: A. paeoniifolius and A. konjac. An Indian Horticulture article is titled "Konjac needs domestication", which reflects that it is still not a developed crop here.
  • Origin and use: native to warm subtropical to tropical eastern Asia, from Japan and China south to Indonesia. The corm's carbohydrate is mainly (over 50%) glucomannan, used in foods and health products.
  • Climate: optimum average temperature of 20 to 25 C, growing up to 2,500 m altitude. Moderate shade of 50 to 70% is reported to raise corm weight in overseas work. Suitable Indian sites, if any, are likely to be cool, humid hill areas, but no Indian trial confirms this.
  • Soil and water: well-drained, fertile, moist soil; soil moisture near 75% of field capacity is best, falling to about 60% as the corm matures. Waterlogging is a risk to corms.

Planting and growth cycle (from overseas references)

  • Propagation: by corms or corm pieces, and by tissue culture. Indian availability of true A. konjac planting material is unverified; confirm the species with a botanist, since several Amorphophallus species look alike.
  • Planting: at the start of the rainy season in pits of about 60 x 60 x 45 cm filled with soil, manure and fertiliser mix.
  • Cycle: food-grade corms can be harvested 1 year after planting, and industrial corms after about 3 years. Flowering begins at around 4 years. One overseas study reported that after 3 years the mother corm could reach 600 to 1,000 g with 44 to 47% glucomannan.
  • No Indian per-acre yield, spacing recommendation or fertiliser dose for konjac was found. Overseas numbers should not be copied to Indian conditions without a local trial.
💡 Tip: Ask ICAR-CTCRI (Thiruvananthapuram, the tuber crops institute), your state horticulture department or a Northeast ICAR centre whether any konjac trial or buy-back is running before spending money on planting material.

Cost, returns and market

  • No verified Indian price for fresh or dried konjac corm, chips or glucomannan flour was found, so no per-acre profit is given here. Any figure quoted by a plant seller should be asked for in writing, with the buyer's name.
  • Glucomannan is made by drying corm slices and milling them; this needs a processor, and no Indian processor taking farm-gate konjac is verified. Selling it as a food ingredient also involves FSSAI rules.
  • Be careful with offers of cheap "konjac seed" with guaranteed buy-back. A crop that takes about 3 years for industrial corms ties up land with no income and no proven buyer.
  • For group arrangements and processing, see FPO and subsidy finder. No konjac-specific subsidy rate was verified.

Sources