How to grow Andrographis paniculata seeds? Detailed explanation of sowing and seedling raising methods
Andrographis paniculata, also known as spring lotus autumn willow, yi jian xi, olive kernel lotus, etc., is an annual herbaceous plant of the genus Andrographis in the Acanthaceae family. As a medicinal herb it has the effects of clearing heat and detoxifying, reducing inflammation, and reducing swelling and relieving pain. It is commonly cultivated in Fujian, Guangdong, Hainan, Guangxi and Yunnan in China, and has also been introduced in Jiangsu and Shaanxi. Now let us take a look at how to grow Andrographis paniculata seeds!
Site selection and land preparation
Andrographis paniculata likes a high-temperature and humid climate. It likes sufficient sunlight and likes fertilizer. The suitable temperature for seed germination and seedling growth is 25-30°C. When the temperature drops to 15-20°C, growth slows down; when the temperature drops to about 8°C, growth stops. When exposed to low temperatures of about 0°C or frost, the whole plant withers. It is suitable for cultivation in fertile, loose, well-drained acidic and neutral sandy loam soil, and can still grow normally in alkaline soil with a pH of 8.0.
Seed treatment
Andrographis paniculata commonly uses the seedling transplanting method or the direct sowing method, with the seedling transplanting method being the main one. When the fruits turn a uniform brown in September to October, pick them in batches in the morning before the dew has dried, place them in a shady and cool place to after-ripen for a few days, and cover them with a cover to prevent loss from seeds bouncing out. After the pods have all split open, sift out the fruit skins to obtain the seeds. Andrographis paniculata seeds are tiny, with a thousand-grain weight of 0.93-1.52 grams. The seed coat is hard and covered with a layer of waxy substance, so the sowing technique requirements are relatively high. Before sowing, the seeds should be rubbed with fine sandpaper or sand to remove the waxy seed coat, then soaked in warm water, then placed in a 30°C incubator for germination, and then sown.
Sowing time
The seedbed soil for Andrographis paniculata should be fertile and loose, raked level and fine. In Guangdong, Fujian and other places, sow in spring from late February to early March, and in autumn sow in July on high-raised seedbeds. In Jiangsu, Zhejiang and Sichuan, use hotbeds for seedling raising in mid-to-late March, and cold frames for seedling raising in April. In North China and Northwest China, greenhouses should sow in early-to-mid March, hotbeds in early April, sunny beds in mid-April, and plastic tunnels are suitable for sowing from April 15-20.
Seedbed management
Seedbed management for Andrographis paniculata mainly involves controlling the appropriate temperature and humidity. Before emergence, the seedbed should be kept moist frequently, and the relative humidity in the bed should be kept at 70-80%. After the seedlings emerge completely, soil moisture should be controlled to prevent damping-off disease. When the seedlings are 6-7 cm tall and have 3-4 pairs of true leaves, they can be transplanted. For direct sowing in Jiangsu and Zhejiang, it should not be earlier than mid-to-late April, in Sichuan from mid-April to early May, and in Beijing mid-May is suitable. When cultivating, it is best to divide into two types: seed fields and commercial fields. Seed fields should be transplanted from May to early June, with a row spacing of 50-65 cm and a plant spacing of 30-35 cm. Commercial fields can be planted from late May to early June, with a row spacing of 25-33 cm and a plant spacing of 16-20 cm, planting 105,000-195,000 plants per square millimeter.
Field management
Field management for Andrographis paniculata mainly involves timely watering to help the seedlings grow new roots. After that, cultivate and weed and topdress once every 15-20 days. Topdressing is mainly nitrogen fertilizer, and human and livestock manure water, urea, etc. can be used. Field management is especially important in the three months of June, July and August, when more nitrogen fertilizer should be applied and watering should be done frequently. When the plant height is 30-40 cm, earth can be banked up to prevent wind damage.
Pest and disease control
The diseases of Andrographis paniculata include damping-off, which occurs at the 1-2 pairs of true leaves stage; soil moisture can be reduced, soil can be treated with 50% carbendazim, or the diseased area can be drenched with a 1000-fold solution. Damping-off occurs at the 2-3 pairs of true leaves stage; temperature can be controlled, ventilation should be noted, and seedbed management should be strengthened. Black stem disease occurs at the adult plant stage; field management can be strengthened, waterlogging should be drained promptly, continuous cropping should be avoided, and during the onset period spray or drench the diseased area with a 50% carbendazim 1000-fold solution. For phytophthora disease, spray or shallow-irrigate the diseased area with a 50% carbendazim 1000-fold solution during the disease period. Pests include cotton bollworm, mole crickets and others causing damage.