Zinnia Planting Methods and Key Cultivation Management Techniques
Zinnia is a famous ornamental plant, also known as zinnia, bubugao, fireball flower, opposite-leaf chrysanthemum, etc. It is an annual herbaceous plant of the genus Zinnia in the Asteraceae family, native to Mexico. It has single-petaled, double-petaled, curled-leaf, wrinkled-leaf and various different-colored horticultural varieties, and is widely cultivated throughout China, sometimes becoming wild. Now let us take a look at the planting methods of zinnia!
Propagation Methods of Zinnia
1. Seed propagation: Before sowing, the soil and seeds must undergo strict disinfection treatment to prevent pests and diseases during the growing period. Sowing can be done from early April to late June. For seed disinfection, soak the seeds in 1% potassium permanganate solution for 30 minutes. The substrate is mixed with 2 parts leaf mold, 1 part river sand, 2 parts peat, and 2 parts perlite. Before sowing, moisten the substrate and sow by dibbling. After sowing, cover with a layer of vermiculite. At a temperature of 21-23°C, germination occurs in 3-5 days.
2. Cutting propagation: Zinnia can also be propagated by cuttings, but cutting-propagated seedlings are less uniform than seed-propagated ones. Lateral buds 10 cm long can be selected for cuttings, generally rooting in 5-7 days. Subsequent cultivation management is the same as for seed propagation, and the seedlings are ready for outplanting after 30-45 days.
Planting Methods of Zinnia
1. Plant shaping: If zinnia is not pinched, the plant will have too few lateral branches and fewer flowers. Proper pinching can promote plant dwarfing and increase flower numbers. When seedlings grow to 4 leaves, transplant and pinch to encourage lower branching and form a better plant shape. Begin pinching one week after transplanting, keeping 4 pairs of true leaves, and decide whether to pinch again based on plant growth and branching conditions.
2. Water and fertilizer management: At transplanting, apply 2-3 grams of compound fertilizer to the bottom of the pot. After transplanting, drench the roots with 800x diluted Dexon for disinfection. Within 1 week after transplanting, keep the pot soil moist to promote surface root growth. Once roots reach the bottom of the pot, begin topdressing, fertilizing 2-3 times per week, and also apply 1 supplemental calcium fertilizer application.
3. Timely pinching: Begin pinching one week after transplanting. After pinching, spray once with a fungicide and apply one heavy fertilizer application. About two weeks after the final pinching, the plant enters the reproductive stage. Gradually increase phosphorus and potassium fertilizers, such as spraying 1000x diluted monopotassium phosphate, to promote more and more brightly colored flowers, and correspondingly reduce the amount of nitrogen fertilizer.
4. Temperature and light: Zinnia prefers warmth and sunshine, and is not tolerant of severe summer heat or severe cold. The optimal growing temperature is 18-20°C during the day and 15-16°C at night. Growth is especially rapid in summer, and full-sun exposure can be used directly. If sunlight is insufficient, plants tend to grow leggy and have weaker resistance; additionally, flowering will also be affected.
Pest and Disease Control of Zinnia
1. White star disease
[Symptoms] The disease occurs on zinnia leaves. Initially, small dark brown spots appear, which later develop into lesions with dark brown margins and grayish-white centers, 2-4 mm in diameter. It mostly occurs on lower leaves. In severe cases, leaves curl and wither, and the surface of the lesions bears dark green mold-like growth.
[Control] Strengthen management, apply sufficient fertilizer, cultivate strong seedlings, provide rain protection and shade, enhance greenhouse ventilation, reduce humidity, and promptly remove diseased plant debris. In the early stage of the disease, promptly remove diseased leaves and immediately spray for control. Use 1:0.5:200 Bordeaux mixture plus 0.1% sulfur powder, or 65% zineb wettable powder at 500x, or 75% chlorothalonil wettable powder at 500-800x, or 50% amobam at 800-1000x.
2. Black spot disease
[Symptoms] Small dark brown spots first appear on the leaves, soon expanding into large irregularly shaped spots, 2-10 mm in diameter, reddish-brown in color. As the spots enlarge and increase in number, the entire leaf turns brown and dries up. On stems, the disease starts from the base of the leaf stalk and develops longitudinally, forming dark brown elongated streaks. Symptoms on flowers are similar to those on leaves, and soon the petals shrivel and dry up.
[Control] Choose well-drained locations for planting. Planting density should be appropriate. Avoid continuous cropping. Seeds must be disinfected before sowing. After autumn, diseased leaves, stems, etc. should be collected and destroyed to eliminate infection sources for the following year. Keep seeds from disease-free healthy mother plants. Spray with 50% zineb or mancozeb at 5000x. When spraying, pay special attention to spraying the undersides of leaves evenly.
3. Mosaic disease
[Symptoms] It occurs throughout the country, often causing stunted and degenerate plants. In the early stage of the disease, leaves show slight mottling, which later becomes light and dark green mottling. Symptoms are more obvious on new leaves.
[Control] Eliminating aphids to prevent the disease has a certain controlling effect on zinnia mosaic disease. Attention should also be paid to field sanitation management, and diseased plants should be eradicated to reduce infection sources.
Habits and Planting Cultivation Methods of Zinnia
Scientific name: zinniaelegqnsjacq.
Aliases: opposite-leaf plum, zinnia, bubugao.
Family and genus: Asteraceae, genus Zinnia.
Morphology: Annual herb, stems erect, plant height 50-90 cm, entire plant covered with coarse hairs, simple leaves opposite, ovate to oblong, entire margins, base slightly clasping the stem, flower heads solitary at branch tips, flowers in red, orange, white, yellow and other colors. Blooming period June-October. Achene.
Habits: Sun-loving, drought-tolerant, vigorous, not demanding regarding soil.
Propagation and cultivation: Sow in open ground in early April. Because the taproot recovers slowly after being damaged, transplanting should be done early. Cultivate and weed, topdress 2-3 times. For seed collection, cut off the entire inflorescence after the petals wither and dry it.
Uses: For arranging flower beds and flower borders, and can also be used as cut flowers.
How to cultivate the herbaceous flower zinnia? Zinnia cultivation methods and management points
Zinnia is an annual herb that loves light and warmth, prefers somewhat moist conditions, and can also withstand a certain degree of drought. It is vigorous, and the cultivation soil should be loose and fertile. Poor soil and excessive drought will directly affect the number of flowers, flower color, and flower diameter.Although the heights of zinnia varieties differ, they are generally controlled between 20-30 cm. They are suitable for use in flower beds and flower borders, and are also an excellent material for artistic flower arrangements. Sowing and seedling raising: For zinnia, each gram contains about 125 seeds for large-flowered types, about 300 for medium-flowered types, and about 1,500 for multi-flowered types. The largest use is in flower beds, flower arrangements, and flower borders during the National Day period. The sowing time is generally best controlled in June-July. Some trial autumn sowings have also been done, but due to factors such as temperature, there is a certain impact on flower color and plant shape, so autumn sowing is generally not adopted. The sowing medium uses a relatively loose artificial medium, and bed sowing or tray sowing can be used. If conditions permit, plug tray seedling raising can also be used. The medium requires a pH value of 5.8-6.2 and an EC value of 0.75. After disinfection treatment, keep the sowing medium at 22-24°C, and seedlings emerge in 3-5 days.
Stage One:
Three days after sowing, the radicle emerges. The medium moisture level should be relatively drier; being too wet can easily cause seed rot. However, at this stage, keeping the area around the seeds moist and with sufficient oxygen is very important, so covering with a thin layer of coarse vermiculite or loose rice husk ash after sowing is very beneficial for seed germination, with the covering thickness being such that the seeds are no longer visible. For open seedling raising, shade netting must be added to ensure humidity and lower temperature (if sowing is carried out in a germination chamber environment, appropriate supplemental lighting can be given). No fertilization is needed at this stage.
Stage Two:
Keep the soil relatively moist, neither too wet nor too dry. Too wet easily causes disease, and too dry causes seedling wilting. At this time, the main root grows to 1-2 cm, the cotyledons unfold, the first pair of true leaves begins to grow, and the seedlings can gradually be exposed to light. Fertilization can begin, generally using 0.05% urea or 50 ppm 20-10-20 water-soluble fertilizer. Nitrogen promotes vegetative growth.
Stage Three:
The seedlings enter a rapid growth period, and water management should be strengthened, carrying out a cycle from dry to wet and back to dry. This is beneficial for seedling root growth and can also avoid leggy growth. At this stage, attention should be paid to pest and disease control. Appropriate topdressing can be applied with 0.1% urea or compound fertilizer. For the compound fertilizer type, an N-P-K ratio of 15-15-15 can be used (or according to market supply, the N and K contents can be slightly higher, and the P content can be lower). If conditions permit, the medium and ambient temperature should be appropriately lowered to about 20°C. However, under protected bed-sowing conditions, temperature control is very difficult, and at this stage a full-light environment is needed, otherwise seedlings easily become leggy. According to seedling growth, appropriately control moisture. Pay attention to ventilation in the broader environment to prevent disease occurrence. Spray chlorothalonil or thiophanate-methyl about once every week. If leggy growth appears at this stage, spray B9 immediately to control height.
Stage Four:
The root system has formed well. When there are 3-4 pairs of true leaves, if leggy growth appears, spray B9 immediately to control height. Temperature and humidity requirements are the same as Stage Three. After the hardening-off stage, prepare for transplanting into pots.
Transplanting/Potting: For plug tray seedlings, when there are 2-3 pairs of true leaves, they can be transplanted into pots; for tray-sown or bed-sown seedlings, when there are 3-4 pairs of true leaves, they can also be potted directly. According to plant height and plant diameter requirements, 12×13 nutrition pots are generally used for potting, which can be done in one step without needing to repot again. Plug tray seedlings have less root damage and are easy to establish after transplanting; for open seedling raising, as much soil as possible should be kept when lifting seedlings, and transplanting should be done in the evening or on cloudy days to improve the survival rate.
Light regulation: Zinnia is a sun-loving plant, and both growth and flowering require ample sunlight. Insufficient sunlight easily causes stem node elongation and affects ornamental effect. After potting, the entire growing period does not require shading.
Temperature regulation: Although zinnia loves warmth, under severe summer heat conditions its growth vigor is somewhat weaker and the flowering effect is not ideal. The optimal temperature for growth and flowering is 15-20°C. The sowing date of zinnia is controlled in summer to prepare flowers for National Day. If temperatures above 35°C are encountered during the growing period, growth is generally not affected.
Cultivation management: During the plum rain season, when there is excessive rain, it easily causes overly rapid internode elongation. Attention should be paid to draining accumulated water and spraying B9 at the appropriate time. In summer, when there is long clear weather and little rain, and it is too dry, growth vigor is easily weakened and flower color is affected. At this time, attention should be paid to water and fertilizer management. Throughout the growing period, appropriately control water; alternating dry and wet pot soil is beneficial for root development and height control. For potted plants, fertilize generally once every 7-10 days. Depending on growth conditions, topdressing can be carried out, using 0.2% urea and compound fertilizer alternately, and stopping urea after one month. After flowering, depending on growth conditions, the interval for topdressing compound fertilizer can be appropriately extended. Because the lateral branches of zinnia have the habit of terminal budding and flowering, if natural growth is not controlled, the flowering position will become higher and higher, affecting the beauty of the plant shape. Pinch timely before and after transplanting to control plant shape. Pinching generally retains 2-3 pairs of true leaves. Zinnia can be pruned, but growth after pruning is poorer, so this method is generally not adopted.
Pests and Diseases: The main diseases of zinnia are: damping-off at the seedling stage, bacterial wilt during the growing period, stem rot, and leaf spot; the main pests are: noctuid moths, red spiders, cabbage caterpillars, etc.