Marigold (Tagetes erecta L) is an annual herb of the genus Marigold in the family Asteraceae, with an erect, stout stem, longitudinal thin stripes, and flattened branches. The leaves are pinnate; there are a few glands along the leaf margin. Cephalic inflorescences are solitary; total bracts are cup-shaped with pointed teeth; tongue-like flowers are yellow or dark orange; tubular corolla is yellow. The fruit is linear, basally reduced, black or brown, covered with short hairs; the crown hairs have 1-2 long mangs and 2-3 short, blunt scales. Flowering period is from July to September.
Native to Mexico. It is found throughout China. It can grow at altitudes of 1150 to 1480 m above sea level, mostly in roadside meadows. Marigolds are often sown in the spring and are often used in flower bed settings because of their large flowers and long flowering periods.
Marigold is an annual herb growing 50–150 cm tall. The stem is erect, stout, with longitudinal thin stripes, and the branches are flattened upwards. The leaves are pinnate, 5–10 cm long and 4–8 cm wide, lobes oblong or lanceolate, sharply serrated at the edges, with long, fine-toothed ends of the upper lobes; there are a few glands along the leaf margin. Cephalic inflorescences are solitary, 5–8 cm in diameter, club-like expansion at the tip of the inflorescence peduncle; total bracts 1.8–2 cm long and 1–1.5 cm wide, cup-shaped, with a toothed tip at the tip; yellow or dark orange tongue flowers; 2.9 cm long, inverted ovate tongue, 1.4 cm long and 1.2 cm wide, with long claws contracted at the base, slightly curved at the apex; tubular corolla yellow, about 9 mm long, with 5 fissures at the apex.
The fruit is linear, basally reduced, black or brown, 8–11 mm long, covered with short microhairs; the crown hairs have 1–2 long mangs and 2–3 short, blunt scales. Flowering period is from July to September.
The suitable temperature for the growth of marigolds is 15-25 ° C, the suitable temperature for flowering is 18-20 ° C, and the relative temperature of the air in the growing environment is required to be 60-70%, and the winter temperature is not less than 5 ° C. In summer, the high temperature is above 30 °C, the plant is long, the stems and leaves are loose, and there are few flowers. Below 10 °C, growth slows down. Marigolds are photophilic plants, and sufficient sunlight is very beneficial to the growth of marigolds, and the plants are short and strong, and the flowers are gorgeous. Sunlight is insufficient, the stems and leaves are soft and slender, and the flowers are few and small. Marigolds are not strict with soil requirements, preferably fertile, well-drained sandy loam soils.
Cultivation techniques
Fertilize the furrows
Marigolds do not have strict soil requirements, and soil with a deep soil layer, loose and well drained should be selected. The rake is 20-25 cm deep, so that the top soil is soft and finely broken, and the field surface is flat. Each 667 square meters of seedbed is planted with 200 kg of soil fertilizer, 2 kg of chrysanthemum special fertilizer, the soil fertilizer is turned into the ground, the fertilizer is evenly sprinkled on the furrow surface, and then drawn into the ground with a hoe, and then rake and leveled.
Seedbed management
Spring sown marigolds emerge 6-7 days after sowing, and after the seedlings emerge, it should be noted that the temperature in the seedbed should not exceed 30 ° C, so as not to cause burning seedlings and rotten roots. After the seedlings grow to about 3 cm and the first pair of true leaves are unfolded, attention should be paid to ventilation to prevent growth. The temperature in the seedbed should be maintained at 25-27 ° C, and the ventilation time should be 8-9 am, and should not be ventilated at high temperatures at noon, so as not to cause flash seedlings. In case of strong winds cooling down, stop ventilation. When the average outdoor temperature is stable above 12 °C, it should be selected on a sunny and windless day, and the film should be uncovered to remove the weeds in the seedbed. If there is a shortage of water, it should be sprayed again, and the membrane should be covered, the ventilation opening should be increased, and the watering in the seedbed should not be too diligent, so as to keep the dry and wet between the beds and soils. When the outdoor temperature is stable at 15 ° C, the seedlings should be uncovered and refined, and the watering should be stopped about 7 days before transplanting, and the seedlings before transplanting should be carried out in preparation for transplanting.
Transplanting
Marigold seedlings can be transplanted when the stem is 0.3 cm thick, the plant height is 15-20 cm, and 3-4 pairs of true leaves appear. Wide and narrow rows are used to plant, large rows of 70 cm, small rows of 50 cm, plant spacing of 25 cm, every 667 square meters of seedlings 4500 plants, planted according to the size of the seedlings in separate rows. Mulch film is used to increase the ground temperature and promote the early maturation of flowers. After transplanting, it is necessary to flood irrigation with large water to promote early slow seedlings and early rooting.
Field management
After transplanting, a shallow hoe should be used to protect the mound, when the seedling height is 25-30 cm, a small number of branches appear, and the soil is taken from the ridge ditch and cultivated at the base of the plant to promote adventitious roots, prevent lodging, and inhibit the growth of submembranous weeds. After the soil is cultivated, it is watered according to the soil moisture, and the amount of watering each time should not be too large, do not spread the ridge, and keep the soil dry and wet. Extra-root topdressing is carried out when the flowers are in full bloom, and the spraying time is better after 6 p.m., and 30 kg of urea and 30 kg of potassium dihydrogen phosphate are sprayed per 667 square meters.
Pick to preserve freshness
Marigolds should be picked at low temperatures and high humidity. Marigolds are picked and cut prematurely, and the flowers are often not easy to open normally after being cut. It is usually harvested 1-2 days before flowering.
The time of cutting is related to the variety, usually when 4-6 petals have been loosened, they can be cut. Sometimes it is found that after the harvest of marigold cut flowers, the buds have not yet bloomed, it is prematurely hanging their heads, this situation is mainly due to the premature picking of buds, calyx is still tightly wrapped in buds. It is best to cut the sepals at 90° with the petals. The branches should be cut with 5 internodes or longer in length, but at least two buds on the branches. After cutting for 1 h, insert water to absorb water, then grade by length, bundle 10 sticks one by one, wrapped in cellophane.
Marigold cut flowers have a short shelf life and are not resistant to long-distance transportation. If the harvested marigold is not listed for sale, it should be immediately stored in a cryogenic warehouse, and the storage temperature is 1 ° C-2 ° C, and it is best to insert it into the water for wet storage. The quality of the wet storage water is important, the pH is low, and it is beneficial for marigold cut flowers. Be careful not to insert the leaves into the water as well. The freshness promoter in the flower container is a mixture of silver thiosulfate and aluminum sulfate. Usually all bottle inserts of marigold are called Cornell formulas. To overcome the phenomenon of marigold neck bending, cobalt acetate with a mass fraction of 360×10E-6 can be added to the preservative. The addition of acetothamine-formylphosphonium prevents red marigold from rotting and wilting early.
Home potted plants
Because the marigold plant is not very tall, it is very suitable for family potting, and the family potted plant needs fewer seedlings, and generally does not need to be pre-sown. Seeds can be sown directly in pots. The soil in the pot is solidified, watered thoroughly, until the water penetrates, the seeds are sown on it, and a thin layer of soil is also covered, if the temperature is not high, it should be warm, and the seedling stage is not divided into more, and there is no need to fertilize.
Key value
ornamental
Marigold is a common landscaping flower with large flowers and long flowering periods, and is often used to decorate flower beds, squares, arrange flower clusters, flower landscapes and cultivate hedges. Medium and dwarf varieties are suitable for flower beds, flower paths, flower clusters, and can also be used as potted plants; varieties with taller plants can be used as background materials or cut flowers.
edible
Marigold flowers are edible. It is a famous dish in the flower recipe, the fresh marigold petals are washed and dried, and then wrapped in flour and fried in oil, its aroma will be mouth-watering, just like stinky tofu, it smells very smelly, but it is fragrant after frying, and it is delicious.
environmental protection
Marigold plants have strong resistance and absorption of hydrogen fluoride, sulfur dioxide and other gases, and can also attract nematodes in the soil.