How to Grow Spider Asters From Seed

The long, spindly petals of the spider aster give this flower its common name. The spider aster is actually just one form of the common aster (Callistephus chinensis), a summer annual that grows well in most climates. Spider asters grow readily from seed started indoors approximately six weeks before the last expected spring frost. Planting the seeds inside provides the controlled conditions that ensure the asters germinate and become mature enough to flower by late summer.

Seedling tray
Potting soil
Plastic bag

Instructions

- 1
  Fill a seed starting tray with moist potting soil. A tray divided into individual cells makes transplanting easier, but any type of plant tray suffices.
- 2
  Sprinkle the seeds on top the soil mixture. Sow two seeds per cell on divided trays or plant two seeds per every 2-square inches on undivided trays.
- 3
  Cover the seeds with a 1/4-inch layer of soil. Slide the tray into a plastic bag and seal it closed. The bags prevents the soil from drying during the sprouting process.
- 4
  Place the tray in a 70 degree Fahrenheit location. Spider asters do not require light during the germination period.
- 5
  Remove the tray from the bag after the first sprouts emerge, usually within 10 days of sowing. Move the tray to a warm area that receives full, all-day sunlight.
- 6
  Water the soil when the surface feels dry. Avoid wetting the plants during irrigation, as wet seedling foliage can result in fungal problems.
- 7
  Transplant the spider asters outdoors after all frost danger passes in spring or early summer. Plant the seedlings in a well-drained, full-sun garden bed at the same depth they were growing at in the tray, placing the plants 12 inches apart in all directions.

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