Chrysanthemums are highly adaptable, like coolness, and are relatively cold-tolerant. The suitable growth temperature is 18-21°C, with a maximum of 32°C and a minimum of 10°C. The low temperature tolerance limit of underground rhizomes is generally -10°C. The lowest night temperature during the flowering period is 17℃, and it can drop to 15-13℃ during the flowering period (middle and late). It likes full sun, but tolerates a little shade. It is more tolerant of dryness and most avoids waterlogging. It likes sandy loam soil with high and dry terrain, deep soil, rich in humus, easily fertile and well-drained soil. It can grow in slightly acidic to neutral soil, but PH 6.2-6.7 is better. Avoid continuous work. Autumn chrysanthemum is a long-night day plant, and its stems and leaves grow vegetatively under 14.5 hours of long daylight per day. More than 12 hours of darkness per day and a night temperature of 100 degrees Celsius are suitable for flower bud development. But different varieties respond differently to sunlight.
In spring, chrysanthemum seedlings are young and should be watered less; in summer, chrysanthemum seedlings grow up, the weather is hot, and evaporation is high, so watering should be sufficient. You can water it once in the morning and again in the evening, and use a watering can. Spray water on the chrysanthemum branches and leaves and the surrounding ground to increase the environmental humidity; control water and fertilizer appropriately before the beginning of autumn to prevent the plants from growing too high. After the beginning of autumn and before flowering, increase the amount of watering and start fertilizing, and gradually thicken the fertilizer. In winter, the flower branches basically stop growing, the plant's water consumption is significantly reduced, and the evaporation is also small, so watering must be strictly controlled. It is best to use a watering can to slowly spray water, and do not use strong water to water. In addition to determining the amount and frequency of watering according to the season, it also changes according to weather changes. On cloudy and rainy days, water less or not at all; when the temperature is high and evaporation is high, water more, and vice versa. Generally, when watering flowers, wait until the soil in the pot becomes dry before watering. If it is not dry, do not water. Water thoroughly. But do not flood the flowerpot, otherwise it will cause root rot, yellow leaves, and death of the plant.
When planting chrysanthemum plants, apply enough base fertilizer in the pot. In the future, nitrogen fertilizer can be applied every 10 days. After the beginning of autumn, from when the chrysanthemums are pregnant to budding, you can apply slightly concentrated fertilizer and water once a week; when the buds are ready to bloom, apply another concentrated fertilizer and water, and then stop fertilizing. If superphosphate or 0.1% potassium dihydrogen phosphate solution can be applied to the chrysanthemums once at this time, the flowers will bloom more vividly.
Potting soil
It is advisable to choose fertile sandy soil, first small pots and then large pots. After 2-3 times of repotting, the pots can be fixed in July; the fixed pots can be used for 6 months Mix soil with 3 parts of leaf mold soil, 3 parts of sandy soil and 1 part of cake fertilizer residue. After watering thoroughly, put it in a cool place, and then move it to a sunny place after the plant grows normally.
Watering
In spring, chrysanthemum seedlings are young and should be watered less; in summer, chrysanthemum seedlings grow up, the weather is hot and evaporation is high, so watering should be sufficient. You can water once in the morning and again in the evening. Water once more, and use a spray bottle to spray water on the chrysanthemum branches and leaves and the surrounding ground to increase the environmental humidity. Before the beginning of autumn, water and fertilizer should be properly controlled to prevent the plants from growing too high. After the beginning of autumn and before flowering, increase the amount of watering and start fertilizing, and gradually thicken the fertilizer. In winter, the flower branches basically stop growing, the plant's water consumption is significantly reduced, and the evaporation is also small, so watering must be strictly controlled. It is best to use a watering can to slowly spray water, and do not use strong water to water. In addition to determining the amount and frequency of watering according to the season, it also changes according to weather changes. On cloudy and rainy days, water less or not at all; when the temperature is high and evaporation is high, water more, and vice versa. Generally, when watering flowers, wait until the soil in the pot becomes dry before watering. If it is not dry, do not water. Water thoroughly. But do not flood the flowerpot, otherwise it will cause root rot, yellow leaves, and death of the plant.
Fertilization
When planting chrysanthemum plants, apply enough base fertilizer in the pot. In the future, nitrogen fertilizer can be applied every 10 days. After the beginning of autumn, when the chrysanthemums are pregnant and budding, you can apply slightly concentrated fertilizer and water once a week; when the buds are ready to bloom, apply another concentrated fertilizer and water, and then stop fertilizing. If superphosphate or 0.1% potassium dihydrogen phosphate solution can be applied to the chrysanthemums once at this time, the flowers will bloom more vividly.
Topping and bud thinning
When the chrysanthemum plant reaches a height of more than 10 cm, start topping. When topping, only leave 4-5 leaves at the base of the plant, and remove all the upper leaves. When 5-6 new leaves grow, remove the heart so that the plant retains 4-7 main branches. Branches and buds that will grow in the future should be removed in time. Topping can cause plants to branch and effectively control plant height and plant shape. When topping for the last time, the chrysanthemum plant should be pruned to a certain shape, remove excessive branches, excessive branches and weak branches, and keep 3-5 branches. When budding occurs in September, the buds at the lower end of the plant should be removed, leaving only one bud at the top on each branch.
Disease and Pest Control
Spot blight is also known as leaf blight. It starts to appear in mid-to-late April and damages the leaves. Prevention and control methods: After harvesting flowers, cut off all the plants on the ground and burn them together; in the early stage of the disease, remove the diseased leaves and alternately spray 1:1:lbo Bordeaux mixture and 50% Toshijin l000 times solution.
Fusarium wilt begins from early June to early July. The disease becomes serious after flowering, damaging the entire plant and causing root rot. Prevention and control methods: Select disease-free old roots to save seeds; rotate crops; make sorghum, dig deep ditches, and reduce humidity; pull out diseased plants, and sprinkle lime powder on the diseased holes or irrigate with 50% carbendazim 1000 times.
Pests: Chrysanthemums are planted all year round, providing sufficient nutrients and habitat for pests and mites. Therefore, whether chrysanthemums are cultivated in a net room or in an open field, they cannot escape the harm of pests or pests. Important pests on chrysanthemums include aphids, thrips, Spodoptera litura, beet armyworm, tomato armyworm and two-spotted leafhopper. The minor pests include root cutters, geometrids, leafminers, whiteflies, venomous moths, mealy scale insects, stilts, etc. There are quite a lot of species.
Chrysanthemums (cut flowers or potted flowers) for domestic sales can tolerate the occurrence of a small amount of pests as long as the quality of the flowers is not affected. .
Weeds: Most chrysanthemum cultivation is open field cultivation and is rotated with paddy fields. Generally, common dry field weeds in water and dry rotation fields will occur in chrysanthemum fields. The competitive harm of weeds is related to the cultivation method, grass phase, density, competition period and environmental factors of chrysanthemums. The competition of weeds for water, nutrients, light, etc. can directly cause poor growth and quality decline of chrysanthemums, which is not conducive to the field. Management operations, etc.