(1) Seed selection and seed soaking: soak the sun-dried seeds for 2-3 days, remove 30%-50% of the floating shrinkage grains, take out the precipitated seeds, and dry them for later use. This can not only make the seeds absorb enough water, improve the germination rate and germination potential of the seeds, but also reduce the astringent grains with germs or the shriveled grains that are easy to rot in the soil.

(2) Seed disinfection: soak the seeds with 0. 1.5% potassium permanganate or 1% bleaching powder for 30 minutes.

(3) Accelerating germination: after soaking the seeds in warm water for 4 days, put them in 4 ~ 8℃ 10d.

(4) Low temperature stratification treatment: indoor 1 floor is humid in winter.

Sand layer 1 seeds are layered, and the sand is kept moist. The low-temperature stratification time should be at least 30 days, preferably 60 days, so that sowing can be carried out even under the condition of 10 ~ 30℃