Key Technical Points for Seed Treatment in Cultivated Licorice

Licorice seeds have a hard seed coat and poor water absorption, with a germination rate of only 4-6%. They need to be treated by milling or sulfuric acid to break the hard-seeded state and improve the germination rate and seedling emergence rate.

I. Sulfuric acid treatment method. For each kilogram of clean seeds, use 20-30 milliliters of 80% sulfuric acid and stir evenly. Once uniform sulfuric acid etching marks appear on the seed coat, rinse with clean water and dry in the sun for later use. The treatment time depends on temperature and the amount of acid added. With the same amount of acid, a high temperature means a short treatment time, and a low temperature means a long treatment time. The more acid added, the shorter the treatment time; conversely, the longer the treatment time.

II. Seed coat milling method. Place the seeds on a millstone to a thickness of 3 cm, turning them as you mill. When the seed coat turns yellowish-white, it is ready. Then soak the milled seeds in 40°C warm water for 2-4 hours, remove them, rinse off the mucilage with clean water, and they are ready for sowing.

Using a rice mill to mill the seeds is simple and easy, costs less than the sulfuric acid method, and causes no damage. The key is to control the degree of milling. If milled lightly, the seed coat will not be broken; if milled heavily, seeds will be wasted severely. It is best to feed the material quickly and mill 3-4 times. Externally, it is ready when there is obvious missing seed coat or the seed coat cracking rate reaches over 90%.