The latest course on planting techniques and methods of Calendula

Calendula, also known as everlasting chrysanthemum, marigold, etc., is a herbaceous flower of the genus Calendula of Compositae, originated in Europe, and was introduced into China from abroad after the 18th century. With the introduction of double petals, large flowers and dwarf calendula, the cultivation, research, development and utilization of calendula in China have developed rapidly. Calendula plants are short, dense flowers, bright colors, long flowering period, mostly used in flower beds, flower belts, flower mirror configuration materials, can also be used as grassland edge plants, is the most common herbaceous flowers in early spring gardens and cities. In addition, calendula also has high medicinal and economic value. Let's take a look at the planting technology of marigold.

Growth habits of Calendula

Calendula is native to southern Europe and the Mediterranean coast. Cold-resistant, afraid of heat, like sunny environment.

1. Temperature: the optimum temperature for the growth of Calendula is 7: 20 ℃, the seedlings can withstand a low temperature of-9 ℃ in winter, and the suitable temperature for adult growth is 10 ℃. If the temperature is too low, it needs to be protected by thin film, otherwise the leaves are vulnerable to freezing damage. Calendula grows when the winter temperature is above 10 ℃. With the increase of temperature in summer, the stems and leaves grow vigorously, the flowers become smaller and the petals decrease significantly.

2. Humidity: the slightly wet condition is better for calendula seedlings, which is beneficial to the growth of stems and leaves and improve the cold resistance in winter. The adult plant of Calendula should be slightly dry, which can control the growth of stems and leaves so as not to cause overgrowth. Indoor or greenhouse cultivation, the air humidity should not be too high, otherwise vulnerable to diseases. Ventilation should be strengthened to regulate indoor humidity.

3. Light: calendula likes sufficient sunshine, especially in sunny beds or greenhouse cultivation, which is very beneficial to the growth of stems and leaves, and the seedlings grow sturdily and neatly. Such as too much rain and snow, lack of light, the basal leaves are easy to yellowing, and even the roots rot and die.

4. Soil: fertile, loose and well-drained sandy loam or cultivated soil is suitable. The soil pH of 6-7 was the best, with more branches and larger flowering.

Propagation methods of Calendula

Calendula is mainly sown and propagated, and it can also be propagated by cuttings, often sowing in autumn or in the greenhouse (or sunny border) in early spring. In the south, the seeds can be sown in multiple periods in one year, but mainly in autumn. Calendula has strong adaptability and can overwinter in the open field. Sowing in summer should pay attention to shade and prevent heat. In the north, it is mostly sown in spring, which is usually carried out from April to May, blossoms in early summer, can spend the summer safely in cool places, and blossom again from September to October. It can also be sowed in autumn. After sowing, the seedlings are moved to the cold bed to survive the winter from the end of September to the beginning of October, and then cultivated outdoors in the next spring, or pot culture is moved into the low-temperature greenhouse during frost to maintain 8: 10 ℃ and provide flowers in winter.

The Seedling technique of Calendula

1. Time: the time of raising seedlings can be determined according to the transplanting time. Generally, the seedlings are raised about 50 days before transplanting.

2. Seedling raising method: raising seedlings in greenhouse or sunny bed, mostly in small arched shed. The seedbed chooses the leeward to the sun, and it is better to move from east to west. The width and length of the seedling bed should be film size and easy to manage, and the general width should not exceed 1.3m. The height of arch shed should be about 60cm. The film had better choose the drip-free film with high temperature and good heat preservation performance.

3. Land selection and bed consolidation: it is suitable to choose sandy loam or cultivated soil with fertile soil, loose soil and good drainage. Rake deep 20~25cm to make the surface soil soft and fine, and the field smooth. Apply rotten high-quality farm fertilizer 4000kg, urea 12kg, potassium sulfate 5kg, phosphate fertilizer 70kg and fine sand 30kg to every 667m2 seedbed, mix well and sprinkle it into the ground, then rake fine and level it.

4. Seed treatment: first select seeds to remove impurities and blighted seeds to ensure that the seeds are full. Then drying seeds in order to kill bacteria, enhance seed vigor and improve germination rate. Before sowing, soak the seeds in 35-40 ℃ warm water for 3-4 hours, remove them and drain them with clean water. Control dry water to sow seeds. In order to prevent seedling diseases, methyl topiramate or chlorothalonil can be used to treat seeds.

5. Sowing: sowing should be carried out on a windless and sunny day. Fill the seedling bed with water on the sowing day and sow the seeds after the water seeps down. Using the sowing method, the treated seeds were first mixed in fine sandy soil and removed on the seedling bed for 2 to 3 times, which should not be too dense, and the sieved soil 0.7~lcm was covered after sowing.

6. Nursery bed management: the suitable temperature for germination is 20: 22 ℃. Generally, the seedlings will emerge 6-7 days after sowing. After the seedlings are all seeded, the temperature in the seedbed should not exceed 30 ℃, so as to avoid burning seedlings and rotting roots. After the seedlings grow to 3cm or so and the first pair of true leaves unfold, attention should be paid to ventilation to prevent overgrowth. The temperature in the seedbed should be kept at 25: 27 ℃, and the ventilation time should be at 8: 9 am. Do not ventilate at noon when the temperature is high, so as not to cause flashing seedlings. In case of strong wind and cooling weather, stop ventilation. When the average outdoor temperature is more than 12 ℃, we should choose a sunny and windless day to uncover the film and get rid of weeds in the seedbed. If you are short of water, you should spray through the water, cover the film, increase the vents, and the watering in the seedling bed should not be too frequent, in order to keep the dry and wet between the bed and soil. When the outdoor temperature is stable at 15 ℃, we should uncover the plastic film seedlings, stop watering about 7 days before transplanting, and rely on the seedlings before transplanting for transplanting.