Detailed Explanation of Key Technical Points for Seed Collection and Seedling Cultivation of Sichuan Pepper

Sichuan pepper (scientific name: Zanthoxylum bungeanum Maxim.), also known as hui, da jiao, Qin pepper, Shu pepper, Chuan pepper or mountain pepper. It is a deciduous shrub or small tree of the Rutaceae family, Zanthoxylum genus, and can be planted alone or used as a protective thorn hedge. Its fruit peel can be used as a seasoning, aromatic oil can be extracted from it, and it can also be used as medicine; the seeds are edible and can also be processed into soap. Sichuan pepper can remove the gamy odor of various meats; promote saliva secretion and increase appetite; and dilate blood vessels, thereby helping to lower blood pressure. It can generally be eaten by most people, but pregnant women and those with yin deficiency and excessive fire should avoid it. The fruit is round, about the size of a mung bean, and its outer peel is a commonly used spice. When the fruit ripens, the red or purple-red peel is called pepper red, and the seed is called pepper eye; both are Chinese medicinal materials and commonly used household seasonings. It is mostly found on slopes at an altitude of 2500 m, and is also cultivated. It is drought-tolerant and likes sunlight, and is cultivated in many places. 

Seed collection

The variety is Dahongpao. Select vigorous trees in full fruiting stage (10-15 years old). From mid-August to early October, collect seeds when the fruit peel changes from green to reddish-brown or purple-black. Place freshly collected fruits in a ventilated place to dry in the shade, remove the fruit peel and impurities to obtain the seeds. After drying, the seeds must never be exposed to the sun, to prevent the seeds from producing oil and losing germinating ability.

Seed storage

After the seeds are collected, if they are not sown in autumn or winter, they need to be stored. There are three kinds: dry storage, wet storage and manure storage:

Dry storage: Put the seeds into gunny bags or porcelain jars and place them in a ventilated and dry place for spring use.

Wet storage: There are three methods.

1. Rinse the degreased seeds clean and mix them with sand, spread them in a cool place to dry, put them into gunny bags and place them in a ventilated and cool place for later use (for the degreasing method, see seed treatment before sowing).

2. Dig a pit for sand storage: For non-degreased seeds, dig a ditch in a place sheltered from the wind and facing the sun with good drainage, 0.8 m deep and 1 m wide, with the length depending on the amount of seeds. Place a straw bundle upright every two meters to facilitate ventilation. Mix the seeds with wet sand at a ratio of 1:2, store them in the ditch, pile them to about 16 cm above the ditch edge, cover with pure wet sand level with the ground, then cover with soil in a ridge shape and press firmly, leaving drainage ditches on both sides. During storage, turn the seeds frequently.

3. Dig a pit for soil storage: For degreased seeds, dig a small cellar 60 cm deep and 30 cm wide at the bottom. After putting the seeds in, spread them in a thin layer 30-40 cm long, then cover with 30 cm of soil. Irrigate an appropriate amount; after the water seeps into the soil, cover with 30 cm of wet soil.

Manure storage: Mix fresh cow dung with seeds at a ratio of 6-10:1, make it into cake shapes and bury it in a pit about one chi deep, cover with about 10 cm of soil, tread firmly and cover with grass. Take it out the following spring, break it up and sow together with the cow dung.

Seed treatment before sowing and selection of sowing time

Degreasing treatment: Seeds that have undergone wet storage and manure storage do not need treatment when sown in spring. Production technology of Schisandra chinensis. Dry-stored seeds for seedling cultivation must undergo degreasing treatment. The method is to use alkaline water or washing powder water of different concentrations and soak for different times to remove the oily substances on the seed coat.

One method is to dissolve alkali or washing powder in warm water, add cold water, keep the concentration at 1-3%, soak the seeds in it for two days, rub and wash to remove the oil from the seed coat shell, take out the pure seeds and rinse twice before sowing.

The other method is to soak in 50% alkaline water for 15-20 minutes at a water temperature of 30-40°C. After taking them out, rinse several times with clean water, then repeatedly rub with plant ash or coarse sand until the seed surface turns grayish-white, then wash clean with clean water, and sow after slight drying.

Determination of sowing time: There are four types: sowing as soon as collected, autumn sowing, winter sowing and spring sowing, with spring sowing and sowing as soon as collected being the main ones.

Sowing as soon as collected: After harvest, sow without storage

Autumn sowing: The time is after White Dew and before Frost's Descent. After degreasing treatment, the seeds need to absorb water and swell before sowing.

Winter sowing: Sow around the Beginning of Winter. After Awakening of Insects the following year, press the soil once.

Spring sowing: The time is after the soil thaws, that is, from mid-March to early April. Seeds that have undergone wet storage and manure storage are sown directly. Dry-stored seeds need degreasing treatment and water absorption and swelling. When the seedbed has good moisture, germination promotion treatment can be carried out, and boiling water can be used to scald the seeds. Method: Pour the seeds into twice their amount of boiling water, stir for 2-3 minutes, soak in warm water for 2-3 days, and when a few seed coats split, take them out and place them in a warm place covered with a wet cloth, and sow after sprouting.

Seedbed preparation and sowing

The seedling-raising site is selected on sandy loam soil sheltered from the wind and facing the sun with deep and fertile soil. Before sowing, apply 30-35 tonnes of farmyard manure per hectare, prepare the land carefully, with no weeds or stones and fine soil. The seedbed is 10 m long and 1 m wide. In dry plateau areas, use a low bed. For drilling, the ditch spacing is 20 cm and the sowing spacing is 5 cm, requiring 112-187 kg of pure seeds per hectare. For broadcasting, mix in plant ash weighing twice the seeds, requiring 225-330 kg of seeds per hectare. After sowing, cover with 2-3 cm of fine pen soil (horse and cattle livestock manure), press slightly, and cover with plastic film or wheat straw to keep the seedbed moist.

Seedbed management

Before and after germination, irrigate when the seedbed is dry. After germination, remove the covering on cloudy days or in the evening to promote rapid seed germination and uniform emergence. When the seedlings are about 5 cm high, carry out the first thinning combined with loosening the soil and weeding, leaving one plant every 2 cm. When the seedlings are 10 cm high, carry out the second loosening of the soil, weeding and thinning, leaving one plant every 5 cm. When the seedlings are about 15-20 cm high, carry out the third loosening of the soil, weeding and final thinning, leaving about 30 seedlings per square meter. After thinning, fertilizer can be applied as appropriate, requiring small amounts and frequent applications.