How to Plant Cosmos Seeds? A Detailed Guide to the Latest Planting Methods
Cosmos is an annual or perennial herbaceous plant of the genus Cosmos in the Asteraceae family, native to Mexico. After Columbus discovered the New World, sailors collected its seeds and brought them back to Europe to plant. Because it is lovable in appearance and easy to cultivate, it quickly spread from gardens to the countryside and mountain forests, taking root across the European continent. Now let us take a look together at how to plant cosmos seeds!
Sowing Time
If cosmos is to bloom in summer, it should be sown from February to March in early spring, preferably under conditions where both temperature and humidity can be controlled. If sowing in the open air, it should be sown in mid-April when the temperature is suitable; when the temperature is suitable, seedlings will emerge in about a week.
Sowing Medium
For the sowing medium of cosmos, choose loose soil rich in organic matter, and apply a certain amount of decomposed organic fertilizer before sowing. When sowing, mix the seeds evenly with a certain amount of sand and scatter them evenly over the seedbed, then cover with about one cm of soil. After sowing, keep the soil moist and control the temperature at around 18°C for germination.
Seedling Stage Management
When cosmos seedlings grow 4 to 5 true leaves, they can be transplanted into nutrient pots and pinched. During the seedling growth period, no additional topdressing is needed, so as to avoid excessive vegetative growth of branches and leaves, which would affect flowering.
Growth Stage Management
Cosmos plants are relatively tall, with slender stems and large, beautiful flowers. When exposed to wind or other harsh weather, they tend to lodge, which affects their ornamental value. Therefore, cosmos needs to be pinched multiple times throughout its growth process, and watering should be reduced. Doing so not only promotes branching but also dwarf the plant, avoiding lodging during growth.
Pest and Disease Control
1. Red spider mite: Cosmos is prone to red spider mites when it is hot and dry. Whether you like it or not, the probability of cosmos getting red spider mites is very high; even if you plant only two plants, red spider mites may still appear. They should be detected and controlled early. At the initial stage, spray 40% dicofol emulsifiable concentrate at 1000 to 1500 times dilution.
2. Powdery mildew: Do not plant too densely; maintain good ventilation and light transmission. After the disease occurs, promptly cut off and destroy diseased leaves and diseased plants to strictly prevent reinfection. At the initial stage of the disease, spray 15% triadimefon wettable powder at 1500 times dilution, or 10% wettable powder at 1200 to 1500 times dilution, alternating the two agents and spraying 2 to 3 times continuously.