When you buy Flammulina velutipes, you should select the one with good roots, and you'd better take some soil. Cut out the darker and harder roots, and cut more the denser ones. Then wrap the cut roots with plastic bags for standby.
Prepare water, baking soda and a container of suitable size and depth. Add about 2 teaspoons of baking soda and a proper amount of water into the container. The water should not be too much, just about half of the root. Mix and stir. Mix baking soda completely. If there is no bicarbonate, it can be replaced by edible alkali.
Put a few wet wipes or make-up cotton in the water, put the cut roots in, and then put the fresh-keeping thin seal in the shade and wait for roots. The life force of Flammulina velutipes is very tenacious. It can grow on its own in alkaline and humid environment. It only needs to control the temperature between 5 ℃ and 10 ℃.