How to Grow Pinellia ternata? A Detailed Explanation of Key Cultivation Techniques
Pinellia ternata is the dried tuber of the Araceae plant Pinellia ternata (Pinelliaternata), also known as hemp taro, three-step jump, and wild taro. It is a commonly used traditional Chinese medicine, with the functions of drying dampness and transforming phlegm, descending adverse qi and stopping vomiting, and dispersing distension and resolving masses. It is mainly produced in Sichuan, Hubei, Anhui, Jiangsu, Henan, Shandong and other provinces, among which Sichuan Province has large output and good quality. It is distributed in most areas of China.
(1) Morphological characteristics
Perennial herb, plant height 15 cm to 40 cm. Underground tuber spherical or oblate spherical, diameter 0.5 cm to 4 cm, with many fibrous roots at the base of the bud, the bottom and lower half pale yellow, smooth, some large tubers used as seed for consecutive years often have several small block-like lateral buds connected around them. Leaves basal, with long petioles; leaves of one-year-old plants or those growing from smaller bulbils are ovate-cordate or anterior-shaped simple leaves; those of plants more than two years old are trifoliolate compound leaves, leaflets elliptical to lanceolate, the middle one larger, 5 cm to 15 cm long, 2 cm to 4 cm wide; apex acute, base cuneate, entire, smooth and hairless. An ovate bulbil is borne on the inner side of the lower part of the petiole, and occasionally another small bulbil is borne at the junction of the leaflets. Flowers unisexual, monoecious, spadix terminal, spathe green or green-purple, lower part tubular and not opening, upper part slightly opening; female flowers borne at the base of the inflorescence, male flowers above the female flowers. Berry green, ovate, seed 1, gray-green. Flowering period May to July, fruiting period August to September, see Figure 4-5.
(2) Growth habits
Pinellia ternata is a shallow-rooted plant that likes fertilizer. It originally grew wild mostly on moist, loose and fertile sandy loam or humus soil. It likes a mild, humid climate and shady environment, is afraid of drought, and avoids high temperatures. In summer, it is suitable for growth in a half-shade and half-sun environment; when soil moisture content is 20% to 40%, growth is relatively suitable; drought and lack of water easily cause seedling collapse. Generally, with changes in the growing environment, it can collapse 1 to 3 times a year. For Pinellia ternata, seedling collapse is, on the one hand, an adaptation to unfavorable environments, and more importantly, it increases the number of bulbils, that is, it carries out one round of asexual reproduction using bulbils as propagation material.
Pinellia ternata begins to sprout and grow at 8C to 10C, begins to germinate and emerge at 15C, with 15C to 26C being the most suitable growth temperature. Growth slows above 30C, and when it exceeds 35C and there is a lack of water, seedling collapse begins to appear, surviving unfavorable environments as underground tubers. When autumn becomes cool, the seedlings emerge again and continue to grow. After autumn, when the temperature is below 13C, the leaves begin to wither.
The tubers, bulbils, and seeds of Pinellia ternata all have no physiological dormancy characteristics. Seed lifespan is 1 year.
For tubers sown in winter or early spring, when the ground temperature at 1 cm to 5 cm below the surface reaches 10C to 13C, the petiole emerges. At this time, if the surface air temperature continues to be lower than the above ground temperature for several days, the petiole grows horizontally in the soil and simultaneously produces one generation of bulbils. The longer the difference between ground and air temperature lasts, the longer the petiole grows horizontally in the soil, and the larger the underground bulbils grow. When the air temperature rises to 13C to 15C, the petiole then grows upright out of the ground.
(3) Cultivation techniques
1. Varieties: Variation among wild populations of Pinellia ternata is very large, mainly manifested in leaf shape, bulbil attachment position, and tuber shape. Because the cultivation history of Pinellia ternata is relatively short, no relatively stable varieties have yet been bred. Preliminary studies show that narrow-leaf Pinellia ternata has higher yield.
2. Site selection and land preparation: Loose, fertile, moist sandy loam with irrigation and drainage conditions is most suitable. Heavy clay soil, saline-alkali land, and waterlogged lowland are all unsuitable for planting. The previous crop should preferably be a leguminous crop, and continuous cropping for 1 to 3 years is possible. Pinellia ternata has a shallow root system, generally not exceeding 20 cm, and likes fertilizer. Therefore, before sowing, in combination with land preparation, base fertilizer should be applied. For every 1000 sq m, apply 8000 kg of farmyard manure, 150 kg of cake fertilizer, and 80 kg of superphosphate. Plow shallowly and harrow finely, level the land, and make beds 1 m wide; the length should not exceed 20 m to facilitate irrigation and drainage.
3. Propagation methods: In production, tubers and bulbils are mostly used for propagation. Seedling raising from seeds or asexual rapid propagation by tissue culture can also be used.
(1) Seed propagation: Harvest seeds when the spathe turns yellow and withered. Seeds collected in summer can be sown immediately after collection. Seeds collected in late autumn can be stored in sand until sowing in March of the following year. Dig shallow furrows 2 cm deep at a row spacing of 10 cm, scatter the seeds in, level the soil, and keep it moist to allow emergence. In the first year, the first leaf is an ovate-cordate simple leaf, and there is generally no bulbil on the petiole. In the second year, there are 3 to 4 cordate leaves, occasionally compound leaves composed of 3 leaflets, and bulbils can be seen. Seedlings can form tubers with a diameter of 0.3 cm to 0.6 cm in the same year, which can be used as seed tubers for the second year.
(2) Bulbil propagation: Bulbils of Pinellia ternata can take root and sprout upon contact with soil. In production, mature bulbils can be harvested from May to June and sown in prepared beds at a row spacing of 10 cm and plant spacing of 3 cm in furrows 3 cm deep, covered with 2 cm of soil. In the same year, 1 to 3 leaves can grow, and tubers of 1 cm to 2 cm can be formed.
(3) Tuber propagation: At harvest, select tubers of the current year with a diameter of 0.5 cm to 1.5 cm as seed. Generally, plant when the average spring temperature is about 10C. On prepared beds, open furrows 4 cm to 5 cm deep at a row spacing of 20 cm. The bottom of the furrow should be level, and place seed tubers in two crossed rows in the furrow at a plant spacing of 3 cm, with buds facing upward, cover with soil, level, and press slightly. It can also be planted in autumn in combination with harvest, generally from late September to early October, using the same method as spring sowing. For every 1000 sq m, use 100 kg to 120 kg of seed tubers.
4. Field management
(1) Irrigation and drainage: After sowing, seedlings generally emerge in spring in 20 days. If there is severe drought, water appropriately to ensure full stands. After full emergence, cultivate and weed in time, and control watering to prevent excessive aboveground growth and improve drought and heat resistance. After May, as the temperature rises, water more to keep the bed surface moist so as to delay seedling collapse. In the rainy season, if water accumulates, drain it promptly to prevent root rot.
(2) Topdressing and earthing up: Pinellia ternata likes fertilizer, and bulbils can develop well only in the soil, so timely topdressing and earthing up are important measures to increase yield. In late May or early June, when bulbils have formed and begin to fall off, for every 1000 sq m, apply 1000 kg of barnyard manure and 8 kg of urea, mix well, scatter in the furrows, and earth up the soil between rows onto the Pinellia ternata seedlings, just enough to cover the bulbils, without covering the leaves in the soil. The number of earthings up can be determined according to plant growth, generally 2 to 3 times. In addition, in the later growth stage of Pinellia ternata, spraying 0.2% potassium dihydrogen phosphate or 500 PPm a-NAA once every 10 days as a foliar application has a certain yield-increasing effect. If seeds are not to be kept, remove the flower scapes in time.
(3) Shading: In production, corn and legume crops can be intercropped along the bed edges in mid-to-late April. In early-to-mid June, the intercrops grow tall or trellises are set up for shading. After September, as the temperature gradually drops, the intercrops should be harvested in time.
5. Pest and disease control
(1) Root rot: This disease is prone to occur in high-temperature seasons when water accumulates in the field. After onset, underground tubers rot, and the aboveground parts then collapse and die. Control methods: mainly pay attention to drainage, pull out diseased plants, and treat diseased holes with 5% lime water or pour it on the roots. Seed soaking with 0.5% to 2% lime water for 12 to 30 hours at sowing can also be used.
(2) Viral disease: The specific manifestations are leaf curling and mosaic. It mostly occurs in spring and summer. After onset, diseased plants should be pulled out and burned, and the site disinfected with lime.
(3) Red hawk moth: The larvae damage leaves, mostly occurring after May. It can be controlled by spraying stomach poisons such as trichlorfon or by manual capture.
(4) Harvesting and processing
Harvest in late September when the leaves turn orange-yellow. Harvesting too early affects yield; too late makes peeling and sun-drying difficult. Fresh Pinellia ternata that needs processing after harvest should be peeled promptly; if piled too long, peeling becomes difficult. The method is to put fresh Pinellia ternata into baskets or gunny bags, wear rubber shoes, and tread with feet to remove the outer skin. A Pinellia ternata peeling machine can also be used. Wash clean and sun-dry or oven-dry; this is raw Pinellia ternata. The drying ratio is (3 to 4):1. Those with large size, clean skin, white color, firm texture, and abundant powder are considered best.
Pinellia ternata used as seed can be stored over winter by sand storage.