How to grow China aster from seed

 

The scientific name of China aster is Callistephus chinensis and is also known as summer aster. The China aster plants are actually a popular and beautiful cut flower. The China aster plants typically grow twelve to thirty-six in height and they produce a dozen or more blooms per plant, although depending on the cultivar. The plants can be grown in the greenhouse or the field. It is possible to grow China aster plants year-round in a heated greenhouse or in moderate climates. This annual should not be confused with the perennial asters (New England aster, September aster, and New York aster). The China aster plants are relatively easy to grow except for its susceptibility to aster yellows, which is a disease that is transmitted by leaf hoppers.

 

How to grow China aster from seed

Site Requirements: Make sure you choose a sunny plot with fertile, well-drained soil that have a pH of 5.5–7.5.

Planting: Transplanting is highly recommended. Sow the China aster seeds 1/8 deep in flats indoors six to eight weeks before danger of last frost. Make sure you keep the soil consistently moist during germination, water it gently with a fine nozzle or mister. For best germination you can maintain a consistent soil temperature of seventy to seventy-two degree Fahrenheit. The China aster seeds should germinate in ten to fourteen days. Once they have germinated, the ideal temperature range is seventy degree Fahrenheit during the day and sixty to sixty-two degree Fahrenheit during the night. After the first true leaves appear you can transplant into cell packs or 3–4” pots. Don’t allow the plants to become root bound. Plants exposed to long days (fourteen hours of daylight or more) during the first four to five weeks of growth will produce flowers more quickly, and on longer stems, than those that are not exposed to long days. Therefore, if you are growing them indoors, you may wish to supplement with artificial light. You need to harden-off transplants by gradually introducing them to outdoor conditions after danger of frost has passed. Transplant into the field with a spacing of about 6–12” between plants. Planting on black or IRT (Infrared Transmitting) plastic film mulch will aid in warming the soil and weed suppression. If direct seeding, sow the China aster seeds 1/8” deep after the last frost when the soil temperature is sixty-five to seventy degree Fahrenheit. Thin them to 6–12”.

To prevent the plants from damage from leaf hoppers, cover the plants with row cover. Make sure you monitor the plants and remove the covers just before flowers bloom. The China aster plants typically require support to prevent them from toppling over as they get large. You can easily install a horizontal trellis, such as Hortonova, shortly after transplanting, before the plants begin to elongate and branch. Two layers of trellis are recommended, one placed at 2" below the top growth of the transplants and a second trellis 12-14" above the first. Actually, pinching blooms are unnecessary.

 

How to Harvest China aster

The flowers are usually ready to harvest in about 110–120 days from seeding. You can easily harvest the flowers when the outside ray florets begin to open. If daytime temperatures are warm you can harvest them early in the morning or in the evening when temperatures are lower. Immediately place the stems in water with a floral preservative. The vase life is typically seven to ten days. Asters store best at thirty-three to thirty-five degree Fahrenheit. The China aster plant is not commonly used for dried flowers, however, if you would like to try using it as a dried flower, harvest when flowers are fully open but before the flower sets seeds. You can harvest in the morning while temperatures are still cool but after the morning dew has dried. You can allow the leaves to remain on the stems and hang small bunches of the flowers upside down to dry, choosing a dry, dark, and well-ventilated room for drying the flowers.

 

Disease and Pest Control

One of the most common disease issues with asters is aster yellows. Aster yellows are actually caused by bacteria that are transmitted by leafhoppers. The disease causes a yellowing of the plant and flowers as well as distorted, malformed flowers, weak stems, and increased branching. One of the best means of controlling is row cover to prevent the leafhopper contact with the plants, but take care to remove the cover once the plants begin to flower. Your local agricultural extension office can help you determine if yellow asters is prevalent in your area.

Some other diseases that can inflict China aster plants include:

Aster wilt: Aster wilt is a fungal infection that causes the plant to suddenly wilt and the stem to rot at the soil line. There are wilt-resistant cultivars that are available.

Aster spotted wilt: This particular disease is spread by thrips that causes streaks on the stems or circular patches on the leaves, as well as increased branching.

Root rot and root rust: This is caused by fungus, these diseases cause rust-colored spots and can also result in loss of flower quality and yield.

For all these disease, the infected plants should be discarded.

The primary pests affecting China aster plants are leafhoppers, thrips, aphids, and Japanese beetles. These pests can cause significant damage to the plant. The use of row covers and crop rotation are the recommended means of controlling these pests. The China aster plants are sensitive to some pesticides.