How to Grow Astragalus Seeds? A Detailed Guide to the Latest Planting Methods
Astragalus, also known as cotton milkvetch, Huangqi, and Dushen, is a perennial herbaceous plant of the Astragalus genus in the Fabaceae family. It has been used medicinally for more than 2,000 years and has effects including enhancing immune function, protecting the liver, promoting diuresis, anti-aging, anti-stress, lowering blood pressure, and fairly broad antibacterial action, giving it extremely high cultivation value. Now let us take a look at how to grow Astragalus seeds!
The Growing Environment of Astragalus
Astragalus prefers cool conditions, is cold-resistant and drought-tolerant, fears heat and waterlogging, and is suitable for planting in sandy loam soil with deep soil layers, rich in humus, and strong water permeability. Strongly saline-alkaline land is not suitable for planting. Its roots grow vertically and can reach more than 1 m, commonly known as “whip-pole astragalus”. In sticky, heavy soil the roots grow slowly and become deformed; in thin soil layers the roots tend to grow sideways with many branches, forming a “chicken-claw shape” and poor quality. Continuous cropping is taboo, and it should not be rotated with potatoes or flax. The hard seed rate can reach 30-60%. When direct-sown, it grows only stems and leaves in the first year without flowering, and only in the second year does it flower, set seed, and produce seeds.
Seed Treatment of Astragalus
1. Select seeds carefully: It is best to choose superior individual plants more than 3 years old that are pure in variety, free of pests and diseases, and robust in growth as mother plants. In autumn, when the pods droop and turn yellow-ripe and the seeds turn brown, harvest immediately, collecting as they ripen. After the pods are harvested, thresh, dry, and store them. Before sowing, use water selection and winnowing to select plump, brown, glossy seeds for production.
2. Seed treatment: Astragalus seeds have hard seed coats, so seed treatment must be carried out before sowing to break the seed impermeability and increase the germination rate.
3. Alternating-temperature soaking: A few days before sowing, soak the seeds in 40 degrees C warm water during the day, then change to cold water at night, treating continuously for 3 days and nights. After removing them, put them in an earthen jar, cover with a wet cloth, and place in a warm spot to promote germination. They will sprout in 3-4 days and can then be sown. Alternatively, place the seeds in boiling water and stir rapidly for 1 minute, immediately pour them into cold water, let the water cool to 40 degrees C, soak for another 2 hours, pour off the water, cover with a wet gunny sack and let them sweat for 12 hours, and sow when the seeds swell or the outer coat cracks.
4. Mechanical damage: Evenly mix 1 part fine river sand with 2 parts seeds, spread on a medium-sized roller mill to a thickness of 3-4 cm, and roll until the seed coats become fuzzy and prickly. After rolling, sieve out the seeds, soak them in 20 degrees C warm water for 1 day, pile them in a warm place to ferment, and they will germinate in about 5 days, after which they can be sown. Be careful not to roll and rub the seeds excessively.
5. Sulfuric acid treatment: For old, fully mature, hard seeds, soak them in a 70-80% sulfuric acid solution for 3-5 minutes, then quickly place them under running water to rinse for half an hour, or wash the residual sulfuric acid off the seeds several times with clean water, and sow after they are slightly dry. The germination rate can reach more than 90%.
How to Grow Astragalus Seeds?
1. Sow at the right time: Astragalus can be sown in spring, summer, and autumn. Spring sowing is done around “Qingming”, no later than “Guyu”; summer sowing is done in June-July; autumn sowing is generally done around “Bailu”. Sowing times differ with climate conditions in each place and should be adjusted flexibly. For example, in the south, where temperatures are high, autumn sowing is done in September and seedlings emerge before winter. In the north, where temperatures are low, seedlings have poor resistance and are prone to frost damage, so autumn sowing should be done before winter and seedlings emerge the following spring. In windy, sandy, and arid areas, it is difficult to keep full stands with spring or autumn sowing, and pests are easily attracted when seedlings emerge in spring; sowing in summer from June to July results in neat emergence and robust seedling growth.
2. Direct seeding management: Direct seeding is convenient for field management and is currently used more in production, but it requires a large amount of seed, growth is uneven, and it affects commercial quality and harvesting. Generally, hole sowing or drill sowing is used, and broadcasting can also be used. For hole sowing, open shallow holes on the prepared seedbed beds at a row spacing of 33×27 (cm), sow 4-5 seeds per hole, and cover with 2 cm of soil; the seeding rate is 1-1.5 kg per mu. For drill sowing, open crosswise furrows on the bed surface at a row spacing of 45 cm and a furrow depth of 3 cm. When sowing, mix the seeds evenly with plant ash and human manure and urine, spread evenly into the furrows, cover with 1-2 cm of fine soil after sowing, and press lightly; the seeding rate is about 2 kg per mu.
3. Seedling raising and transplanting: Raising seedlings and transplanting can save land, and after transplanting the plants grow robustly, the rhizomes grow neatly, harvesting is convenient, and the commercial quality is good with high yield, so its use in production has gradually increased in recent years. Open crosswise furrows on the seedling bed at a row spacing of 20-25 cm, with a furrow depth of 3 cm and a sowing width of 10 cm. Mix the seeds evenly with plant ash and sow evenly into the furrows, cover with 2 cm of soil, press lightly, water thoroughly, and cover the bed with grass to preserve warmth and moisture. The seeding rate is 10-15 kg per mu. For spring seedling raising, it is best to use a small arched shed with plastic film to raise seedlings, so as to raise temperature and preserve soil moisture; when temperatures are low, straw curtains can be added for warmth. For summer seedling raising, after the seedlings emerge, in order to prevent sun exposure and maintain seedbed moisture, a shed curtain or black net must be set up for shading, with about 50% shade being best. On rainy days and at night, the shade curtain should be removed so the seedlings can receive dew.
4. Field management: After Astragalus seedlings emerge, field management should be strengthened, weeds removed promptly, and overly dense and weak seedlings pulled out in good time. When the seedlings grow to 13-15 cm and the roots reach 15 cm, they can be transplanted. Transplanting is best done on cloudy days or in the afternoon and evening of sunny days, and the survival rate after transplanting is higher after rain. First separate large and small seedlings, then open holes at a row spacing of 20-24 cm and a plant spacing of 12 cm, and plant 1-2 seedlings per hole. After transplanting or final planting of seedlings, water or spray immediately to help them survive. Generally, about 20,000 seedlings are planted per mu.