Detailed Explanation of Key Techniques for Greenhouse Cultivation of Crown Daisy
Crown daisy, also known as tonghao, penghao, haocai, chrysanthemum greens, tanghao, haozigan, haozi, and tonghuacai (called ecai and yicai in places such as Fujian), is an annual or biennial herbaceous plant of the Asteraceae family, with alternate leaves that are long and pinnately lobed, and yellow or white flowers that closely resemble those of the wild chrysanthemum. The achene is ribbed, and the plant grows two to three chi tall; the stems and leaves are edible when tender and can also be used as medicine. In ancient China, crown daisy was a delicacy of the imperial court, which is why it is also called emperor's vegetable. Crown daisy has the fresh aroma of mugwort and the sweet fragrance of chrysanthemum. According to ancient Chinese medicinal texts, crown daisy is sweet, pungent and neutral in nature, non-toxic, and has the effects of "calming the heart, nourishing the spleen and stomach, eliminating phlegm and fluids, and benefiting the intestines and stomach". It is cultivated ornamentally in gardens throughout China. Wild plants are found in Hebei, Shandong, Shijiazhuang in Hebei and other places.
The stems and leaves of the Asteraceae plant crown daisy. Also known as penghao, chrysanthemum greens, haocai, tonghaocai, yicai (ecai), and aicai, it is an annual or biennial herbaceous plant of the genus Chrysanthemum. The roots, stems, leaves and flowers of crown daisy can all be used as medicinal materials, with effects of purifying the blood, nourishing the heart, lowering blood pressure, moistening the lungs and clearing phlegm. Crown daisy has a distinctive fragrance, and the seedlings or tender stems and leaves are used for stir-frying, cold dressing and making soup. In Europe, crown daisy is used as a flowerbed ornamental. Crown daisy is a shallow-rooted vegetable, with its root system distributed in the topsoil layer. The stem is round, green, and has a mugwort-like odor. The leaves are long, with wavy or deeply lobed margins and thick leaf flesh. The flower head is a capitulum with yellow flowers, and the achene is brown. The seeds used in cultivation, botanically called achenes, are angular, with an average thousand-grain weight of 1.85g. Crown daisy prefers cool conditions and cannot tolerate high temperatures; its optimum growth temperature is around 20°C, growth is slow below 12°C, and growth is poor above 29°C. Crown daisy is not strict about light requirements, and generally weaker light is preferable. It is a long-day vegetable, and under long-day conditions vegetative growth cannot fully develop, and it quickly enters reproductive growth and flowers and sets seed. Therefore, in cultivation it should be scheduled in spring and autumn when daylight is shorter. It is not demanding regarding fertilizer and water conditions, but it is best not to let water accumulate. Crown daisy varieties are divided into two types, large-leaf crown daisy and small-leaf crown daisy, according to leaf size.
Nutritional value of crown daisy
The roots, stems and leaves of crown daisy are all edible and contain a wide range of rich nutrients, especially relatively high levels of carotene and minerals. Its fiber is fine and tender and easy to digest and absorb, which is very beneficial for children's development and growth and for elderly people with poor gastrointestinal absorption. In addition, crown daisy contains relatively high levels of iron, which is somewhat helpful for children's growth and development and for patients with anemia. Furthermore, crown daisy also contains a volatile essential oil as well as substances such as choline, and therefore has effects such as regulating the stomach and strengthening the spleen, lowering blood pressure and tonifying the brain. Eating crown daisy regularly has relatively good therapeutic effects on cough with excessive phlegm, disharmony of the spleen and stomach, memory decline and habitual constipation. And when crown daisy is stir-fried together with meat, eggs and the like, the absorption rate of vitamin A can be increased. Stir-fry crown daisy briefly, then dress it with sesame oil, monosodium glutamate and refined salt; it is light and tasty, and most suitable for patients with coronary heart disease and high blood pressure.
How is crown daisy cultivated in a greenhouse?
Choosing the land. During the vegetative growth period, the stems of crown daisy can reach 20-30 cm in height, so the low southern part of a greenhouse used for growing tall crops (such as kidney beans, yardlong beans, etc.) can be used for planting.
Choosing varieties. Crown daisy has two types, large-leaf varieties and small-leaf varieties, and greenhouse cultivation mainly uses small-leaf varieties. Small-leaf varieties are relatively cold-tolerant, with a growing period of 40-50 days.
Cultivation techniques. For cultivating crown daisy, the soil is required to be kept constantly moist. In order to keep it separate from the planting beds of tall crops, the beds for cultivating crown daisy should be made as independent flat beds to facilitate watering. To promote germination, seeds can be soaked and pre-germinated, and the wet sowing method can be used for drilling or broadcasting. After sowing, cover with 1 cm of soil and cover tightly with plastic film. Generally, 4-5 kg of seed is used per mu.
After emergence, remove all the plastic film, keep the bed surface alternately dry and moist, and at the 1-2 true leaf stage carry out thinning and pull out weeds, keeping the seedlings about 4 cm apart. Pay attention to regularly monitoring the humidity inside the greenhouse to avoid excessive moisture, which can cause diseases in the tall crops in the greenhouse.
During the growth period, apply 1-2 topdressings of quick-acting nitrogen fertilizer along with watering. When the plants reach about 20 cm in height, begin harvesting; it should not be too late, so as to avoid affecting quality. After the first cutting, water and topdress again to promote the development of side shoots, and harvest again after 20-30 days. Each topdressing is 10 kg of urea per mu.