Break the stems of tentis and wash them. Put the tentis in a utensil (made of china clay or plastic). Put sufficient water to submerge the tentis in the utensil and leave it covered in sunlight.
In 5 to 6 days the tenti's green color will change into yellow. Wash these tentis twice with water and keep them in a filter. After 2 to 3 hours the excess water will dry and the tentis will be ready for making the pickle.
Heat the mustard oil and let it cool.
Mix and grind the black mustard seed and asafetida. In this mix the turmeric powder and salt.
Put the tentis in a utensil. Add all the spices and 2 tablespoon oil to tentis and mix them well. Now keep these tentis in a glass container. Keep stirring the pickle in every 2 to 3 days with a clean dry spoon. After 10 days the pickle will start turning sour and delicious. The pickle is now ready.
For longer storage fill the remaining oil in the glass container so that the tentis are submerged in the oil.