Key Technical Points for Seed Treatment in Artificial Cultivation of Licorice

Licorice seeds have a hard seed coat and poor water absorption, with a germination rate of only 4-6%. Grinding or sulfuric acid treatment is needed 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, mix evenly with 20-30 mL of 80% sulfuric acid. Once uniform sulfuric acid etching marks are visible 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, higher temperatures require shorter treatment time, while lower temperatures require longer treatment time. With more acid added, the treatment time is shorter; conversely, the treatment time is longer.

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

Grinding seeds with a rice milling machine is simple and easy to carry out, with lower cost than the sulfuric acid method and no damaging effects. The key is to control the degree of grinding. If ground too lightly, the seed coat will not break; if ground too heavily, seeds are wasted severely. It is best to feed the seeds quickly and grind 3-4 times. When there is obvious missing seed coat on the surface or the seed coat cracking rate reaches over 90%, it is ready.