How to grow yew seeds? A complete guide to the planting method
The yew is known as the "giant panda of the plant world" and is recognized worldwide as an endangered natural rare anti-cancer plant. It is an ancient relict tree species left over from the Quaternary glaciation, with a history of 2.5 million years on Earth. Because the yew grows slowly under natural conditions and has poor regeneration capacity, for a long time no large-scale yew raw material forest base had been established anywhere in the world. Logging is now explicitly prohibited, and most of what is sold on the market is artificially cultivated. But do you know how to grow yew seeds? Below, the editor will briefly introduce how to grow yew seeds!
Collection of yew seeds
Yew seeds mature from late September to early October, and can be collected when the seeds turn dark red. After the seeds are collected, soak them in water for 3-5 days, crush the skin and flesh (the aril flesh), wash them, dry them in the shade, and store them indoors in a cool, dry place.
Choosing a suitable seedling site
The yew seedling site should be forest soil with deep soil layers, a loose structure, plenty of humus, and good drainage, suitable for raising seedlings. The yew has the characteristics of shade tolerance, drought tolerance, and cold resistance, and requires a soil pH between 5.5 and 7.0.
The yew's habitat is shade-tolerant and it can also grow under dense forest, is perennial, and does not form forests. It is mostly found in mixed coniferous and broad-leaved forests dominated by Korean pine. It grows on rocky or thin soil on mountain tops, mostly in shrub form. In its place of origin, the average annual temperature is 2°C to 7°C, and the average annual rainfall is 750-1000 mm. It is mostly scattered under moist, fertile mixed coniferous and broad-leaved forests on shady slopes or semi-shady slopes. It likes a cool and humid climate, can withstand low temperatures below minus 30°C, has strong cold resistance, and its optimum temperature is 20-25°C. It is a shade-loving tree species. It likes moisture but fears waterlogging, and is suitable for planting in loose, moist, well-drained sandy loam.
Land preparation and fertilization of the planting site
After the seedling site is chosen, carry out land preparation and fertilization. Newly opened seedling land has fertile soil and does not need fertilization. Old seedling land must be well prepared and fully fertilized: plow 20-25 cm deep in autumn, then shallow-plow and harrow finely in spring. While plowing, apply decomposed, finely chopped manure, and make seedbeds 15-20 cm high, 1.2 m wide, and 10-20 m long.
Pregermination of yew seeds
Yew seeds are deeply dormant seeds, so pregermination treatment must be carried out before sowing. The two pregermination methods used are as follows:
1. Alternate-year burial pregermination method: Soak yew seeds in 45°C warm water for 3-4 days. When the seeds turn milky white, take them out and disinfect them with a 1-2% copper sulfate solution, then mix them evenly with wet sand at 60% relative humidity equal to 3 times the seed volume, put them into straw bags or wooden boxes, and place them in an underground cellar. The cellar should be chosen in a place with the groundwater level below 2 m, high terrain, and good drainage, with a cellar depth of 1.2-1.8 m, and strictly prevent mice from entering. In addition, check the cellar temperature frequently; in summer the temperature must not exceed 18-20°C. When the cellar temperature is high, set up a shade shed above or open the cellar door at night to lower the temperature. Using this method, store the seeds in the cellar in autumn, bury them throughout the second year, take the seeds out in the third year, spread them in the sun for 24 days, and sow when 20-30% of the seeds have germinated radicles.
2. Overwintering burial pregermination method: This method is suitable for sowing seeds immediately after collection, that is, in the autumn of the same year, remove the seed coat from fresh seeds, then soak and disinfect them, and then bury them using the same wet sand burial method as the alternate-year burial pregermination method. 20-30 days before sowing in the following spring, take the seeds out and spread them to dry on a shady slope facing away from the wind, cover them with plastic film to raise the temperature, and pay attention to watering to keep them moist. Once part of the seed shells have cracked, they can be used for sowing.
Sowing of yew seeds and field management
The sowing time is from late April to early May each year, and the sowing rate is 0.045 kg-0.05 kg per square meter of seedbed. When sowing, pay attention to leveling the bed surface and watering the bed thoroughly. Press the seeds on the bed surface with a wooden roller so that the seeds contact the soil, then cover with river sand to a thickness 2-3 times that of the seeds, and press once more after covering with river sand. During the seed germination period, water according to the principle of "water less but often," and prevent bird damage. After the seedlings emerge completely, spray a 1% Bordeaux mixture once every 7-10 days for a total of 5-7 sprays to prevent damping-off of the seedlings.
Two-year-old seedbeds can be given decomposed, diluted human urine and manure 3-5 times, and ammonium sulfate 1-2 times, with each application of ammonium sulfate at 0.1 kg/10 m. After spraying, promptly wash the seedlings with clean water to prevent phytotoxicity. In June and July, apply potassium fertilizer again to increase the degree of lignification of the seedlings.
Overwintering protection of yew seedlings
Yew seedlings require overwintering protection measures. For 1-4 year old seedlings, cover with soil or grass to prevent drought. From Frost's Descent to the Beginning of Winter, cover the seedlings with soil, with the soil covering 4-6 cm above the seedling tips. Do not cover too early, so as to avoid rotting the seedlings. After Qingming, remove the cold-protection soil. To prevent physiological drying of the seedlings, remove it in 2-3 stages, and water promptly after removing the soil.