Calendula Profile

Calendula is a biennial herb of the Compositae family. Its leaves are alternate and oblong. The color of marigolds is often yellow or orange. The flowering period is April to September, and the fruiting period is June to October. It likes to grow in a mild, cool climate, afraid of heat and cold. It is native to southern Europe and the Mediterranean coast.

Calendula is rich in a variety of vitamins, especially vitamin A and vitamin C, which can prevent pigmentation, increase skin luster and elasticity, slow down aging, and prevent skin from sagging and wrinkles. Almost all parts can be eaten. Its petals have the function of beauty, and the flowers contain carotenoids, tomato hydrocarbons, butterfly plum yellow, ruby yellow, volatile oil, resin, mucus, malic acid, etc. The roots of marigolds contain bitterness, Arnichol; the seeds contain glycerides, wax alcohols, and alkaloids. Ancient Egyptians believed that calendula could delay aging, while Indians respected it as a sacred flower. In the Middle Ages, people used marigolds to heal wounds and to fight the plague and the Black Death.

Calendula morphological characteristics

The flower diameter of marigolds is about 5 cm. There are yellow, orange, orange-red, white, and other colors. There are also cultivars such as double petals, curled petals, green hearts, and deep purple flowers. The whole plant is about 20 to 75 cm tall, usually branched from the base of the stem, green or somewhat glandular pilose. Basal leaves are oblong obovate or spoon-shaped. Head-shaped flower head solitary stem branch end, diameter 4 ~ 5 cm, involucre 1-2 layers, lanceolate or oblong-lanceolate, outer layer slightly longer than the inner layer, tip gradually pointed, small flower yellow or orange-yellow It is 2 times longer than the involucre, and the tongue is 4 to 5 mm wide; the eaves of the tubular flower have triangular-lanceolate lobes, all achenes are curved, light yellow or light brown, and the outer achenes are mostly curved inward, often with small outside Acupuncture, with a beak at the top and regular transverse folds on both sides of the winged ridge. The flowering period of the marigold is from April to September, and the fruit period is from June to October.

Calendula growth habit and growing environment and distribution

Calendula is native to southern Europe and the Mediterranean coast. It likes to grow in a mild and cool climate and is resistant to heat and cold. It is required to have sufficient sunlight or slight shade, loose, well-drained, moderately fertile soil, and have a certain drought tolerance. The soil pH for calendula planting should be maintained at 6-7 so that the plants have many branches and the flowers are large and dense.

Temperature condition

The suitable temperature for the growth of marigolds is 7-20 ℃, the seedlings can tolerate a low temperature of minus 9 ℃ in winter, and 0 ℃ for adult plants is suitable. If the temperature is too low, it needs to be protected by a film, otherwise, the leaves are vulnerable to freezing damage. Calendula grows excessively when the temperature is above 10℃ in winter. In summer, the temperature rises, the stems, and leaves grow vigorously, the flowers become smaller, and the petals decrease significantly. The calendula of the seedlings should be slightly wet, which is conducive to the growth of the stems and leaves and improves the cold resistance in winter. Adult plants should be slightly dry to control the growth of stems and leaves, so as not to cause excessive growth.

Lighting conditions

Calendula likes to be hardy, afraid of heat, and like a sunny environment, especially in winter open field seedling or shed cultivation, which requires sufficient sunlight, which is very beneficial to the growth of stems and leaves, and the growth of seedlings is short and tidy. In case of excessive rain and snow and insufficient light, the base leaves are prone to yellowing, and the roots may even rot and die.

distribution range

Calendula is native to Europe and has a long history of cultivation in Europe. After 1949, marigolds were widely cultivated in gardens and used in potted plants and flower beds. After 1980, double-petaled, large-flowered, and dwarf marigolds were introduced to China and have now become one of China's important herbal flowers.

Calendula efficacy and role

Medicinal value

The main pharmacological effects are
①The flower has antibacterial and anti-inflammatory effects, especially for Staphylococcus and Streptococcus. Its antibacterial ingredients are soluble in alcohol but not in the water, and the effect is better in an alkaline environment.
②The effect of lowering blood lipids. The saponins in calendula can reduce serum cholesterol, free fatty acids, phospholipids, β-lipoprotein, total lipids, and triglycerides in experimental hyperlipidemia rats, and affect liver total lipids and cholesterol. And triglycerides also have a lowering effect.
③The polysaccharides in Calendula officinalis have a strong immune-stimulating effect. ④ Calendula flower extract has a calming effect on the central nervous system and can reduce reflex excitability; intravenous injection can lower blood pressure, enhance heart activity, increase heartbeat amplitude, and slow down the heart rate.
⑤ Can promote bile secretion and accelerate wound healing. In Europe, there is a custom of oral administration of calendula chrysanthemum to treat gastric and duodenal ulcers, gastritis, hepatobiliary diseases, etc. If used for gastrointestinal cancer, it can reduce symptoms of poisoning, improve appetite, sleep, etc., and it can also be used for menstrual irregularities. 

Edible value

Calendula is suitable for single brewing or with green tea.
You can brew it with a tablespoon of dried calendula petals, and simmer for about 3 to 5 minutes. The golden yellow tea is set against the floating golden petals, and the fragrance is curled. It is sweet and slightly bitter. You can add honey to taste. Drinking calendula tea when you have a cold can help reduce fever and reduce irritation. It also has antispasmodic and digestive effects, which is very suitable for patients with digestive ulcers. It can also promote blood circulation. It can also alleviate alcoholism, so it is also beneficial to the liver. But pregnant women should not drink calendula tea.

Calendula cultivation

Land preparation

The farmland for planting marigolds should be deep, loose, and well-drained, and air-permeable soil. The first crop should be melons, corn, and beans. When the temperature starts to rise and the arable layer is thawed, use heavy-duty rake belts as soon as possible. The depth of the rake is 20-25 cm, the surface soil is finely broken, and then the ground is suppressed to make the field level. While harrowing the ground, proper fertilization can be made according to the fertility of the soil.

Seed treatment

The seeds should be dried before sowing. You'd better choose a sunny and windless day and spread the seeds on the tent or concrete floor. The thickness is about 1 cm, and it is exposed for 4-6 hours, turning once every 1 hour. Through ultraviolet radiation, pathogenic bacteria on the surface of seeds are killed, seed vigor is enhanced, and the germination rate is increased. The ground temperature rises quickly after the land is covered with plastic film. The sowing date is selected after the complete frost is released, and the average temperature is stable above 13℃. When the surface ground temperature is above 10℃, sowing in time.
Gardeners can use a seeding punch with a diameter of 3 to 5 cm to punch holes at a distance of 35 cm from the centerline of the film, with a hole spacing of 30, and a hole depth of 7 to 8 cm. There are 3 seeds or 4 seeds per hole, and the covering soil should be fine soil with moist sand.

Release seedlings

Generally, seedlings can emerge 5-10 days after sowing. Due to the time of emergence, sowing depth, and soil type. It is closely related to the local temperature. When the seeding is too deep, the soil moisture is too high or the temperature is too low, the emergence time will be delayed. When the seedling is about 5 cm high. When the weather is right, the seedlings should be released in time by breaking the membrane and avoid burning the seedlings.

Thinning, fixed seedling

When the seedling grows 2 to 3 true leaves, thin the seedlings when the seedling height is about 20 cm, and leave 2 strong seedlings in each hole; when 3 pairs of true leaves are fixed, leave 1 healthy and disease-free seedling in each hole; The seedlings and diseased seedlings are removed, and the seedlings are transplanted to supplement the seedlings. Seedling density is based on the principle of fertile land should be thin, lean land should be dense. When the height of the seedlings is about 30 cm, combine weeding, cultivating, and loosening the soil, taking soil from the ditch, and planting on the base to make the base produce adventitious roots to prevent lodging and breaking.

Irrigation and fertilization

Calendula is a moderately water-requiring plant. Lack of water will result in short plants. Excessive irrigation will cause plants to grow longer, which will reduce the yield due to reduced flower size. Generally, water should be irrigated promptly based on the rainfall of the year. In the flowering period, it is necessary to combine fertilization and timely irrigation to promote more flowering and large flowers. Extra-root topdressing can be applied to the fields in the lack of fertilizer and the field during the flower harvest period to promote plant growth and increase the production of flowers in the later period.