When to Sow Aster Seeds
Answering netizens' questions about when to sow aster seeds and the related knowledge of aster seed planting methods, please refer to the detailed introduction below.
Aster, also known as July Chrysanthemum, Jiangxi Wax, Lan Chrysanthemum, and Cui Lan, belongs to the Asteraceae family, Aster genus. It is native to China, Korea, and Japan.
【Morphological Characteristics】
The aster is an annual or biennial herbaceous flower. The plant height ranges from 30 to 80 centimeters, varying with different varieties. The stems are erect, with many branches in the upper part, covered with sparse short hair. The leaves are alternate, ovate to long ovate, with coarse sawtooth edges. The leaves in the upper part of the stem are sessile, while those in the lower part have short petioles.
Capitulum, singly at the branch tip. The center of the inflorescence is composed of yellow tubular flowers, surrounded by several layers of ligulate flowers. Flower colors include red, purple red, white, pink, light blue, and other colors. The stem color is related to the flower color: purple stems tend to have darker flowers; green-white stems tend to have white or light pink flowers. The flowering period is from June to October. Achene, cuneate. Seeds are brown. There are approximately 420 seeds per gram.
After being introduced to Europe from China in 1728, aster has been hybridized and selected by horticulturists from various countries, forming today's extremely rich and diverse cultivated varieties (about 450 varieties). There are many classification schemes and standards, but they are generally divided by plant height and flower type.
According to plant height, there are tall, medium, and dwarf varieties. Tall varieties are 60-90 centimeters tall, robust in growth, with a growth period of over 7 months, late flowering, and are often cultivated as biennial flowers, mainly used for cut flowers. Medium varieties are 30-60 centimeters tall, with a growth period of over 5 months, rich in flower shapes and colors, and generally used for cut flowers, potted plants, and flower beds. Dwarf varieties are 10-30 centimeters tall, with weaker growth momentum, small leaves, and numerous flowers, early and concentrated flowering, suitable for potted plants and flower beds.
【Growth Habits】
Aster prefers warm temperatures, dislikes extreme heat, is relatively cold-resistant, and the minimum temperature for safe overwintering is 2-3°C. It can be overwintered in a cold frame. It grows best in fertile and well-drained sandy soil. It dislikes successive cropping, as continuous planting in the same soil can lead to weakened growth. It is a shallow-rooted plant with poor drought resistance and requires increased irrigation in summer.
【Propagation Method】
Aster is propagated by seeds, and can be sown in spring, summer, and autumn. The specific sowing time can be chosen based on the desired flowering period. Spring sowing is done in March to April in open ground seedbeds, flowering in July to August. Summer sowing is done in June to July in open ground seedbeds, flowering in September to October. Autumn sowing is done in September to October in cold frames, flowering in the following May to June.
The sowing soil is mixed with garden soil, decomposed leaf mold, and sand in a ratio of 2:1:1. Before sowing, the soil should be thoroughly watered to keep it moist. Under room temperature of 16-18°C, moist soil, and good ventilation, seeds can germinate in 6-8 days with a germination rate of about 50%. Transplant the seedlings when they have two true leaves, as older seedlings dislike transplanting, usually only transplanting once.
When to Sow Aster Seeds
【Cultivation Management】
When the seedlings grow to 10 centimeters tall, dig up the seedlings with soil clumps and plant them. The spacing between plants varies with different varieties. The spacing for tall varieties is 30-35 centimeters, for medium varieties 20-25 centimeters, and for dwarf varieties 10-20 centimeters.
Aster likes fertilizer. Use fully decomposed organic fertilizer as a base fertilizer. After the seedlings are planted and recovered, fertilize every half month, but stop fertilizing during the extreme heat of summer. During cultivation, it is not advisable to water frequently. When the seedlings are growing vigorously, they should be tilled to retain moisture, to prevent soil from becoming too wet due to excessive watering or rain, which can easily cause plant lodging and diseases. It is better to let the soil be slightly dry than too wet. However, during the summer growing period, as aster has shallow roots and does not tolerate drought well, it requires frequent watering. To make dwarf varieties look more beautiful and have closely arranged flowers, water should be controlled for a period after the flower buds appear to inhibit the elongation of the main stem, and then watering should be increased when the lateral branches reach 3 centimeters.
To make aster bloom on a specific date, the flowering period can be controlled by choosing the sowing date. For example, for dwarf varieties, to make them bloom from May to June, they should be sown in greenhouses from February to March; to make them bloom from June to July, they should be sown from April to May; to make them bloom in early October, they should be sown in mid-July. If sown in mid-August, the seedlings will overwinter in a cold frame and will bloom in early May of the following year.
Seeds produced by aster in summer are mostly underdeveloped and not suitable for harvest. Generally, mature seeds are harvested from September to October, as the cool and dry autumn weather, with abundant sunlight, is conducive to seed development. When the ligulate flowers in the capitulum begin to wither and white pappus is exposed, the seeds can be harvested in time, dried in the wind, and then packaged in paper bags and stored in a cool and dry place. The life span of the seeds is about 2 years.
Common diseases of aster include:
1. Damping off is prone to occur in the seedling stage, causing the whole plant to wither and die. The seeds can be disinfected by soaking in 1000-3000 times mercuric chloride solution for 10-30 minutes before sowing. Diseased plants should be removed in time, and sprayed with 800-1000 times zineb solution for prevention and control.
2. Rust disease appears as orange spots on the back of leaves at the beginning of the disease, and finally, angular brown spots are produced on the leaf surface, causing leaf withering. Before the disease occurs, Bordeaux mixture can be sprayed at a ratio of 120-160 times to prevent the disease.
3. Black spot disease affects the leaves, producing black-brown angular spots along the veins, causing leaf death and falling. Use 70% thiophanate-methyl 800 times solution for control.