Aster Planting and Care Guide

The Aster plant is as versatile as it is beautiful! Depending on its height, the plants are perfect for borders, rock gardens, or wildflower gardens. Use them as cutflowers too. Asters are valuable pollinator plants for bees and butterflies, and the tasty seed heads are sought by birds.

Aster flower seeds can be started indoors 6 - 8 weeks prior to the end of frost season or directly seeded outdoors in the spring. Perennial Aster seed does best with a 30 day cold treatment prior to starting the seeds, but annual Aster seed does not require the cold treatment.

Asters grow and flower best in full sun. Some varieties will tolerate part shade but will have fewer flowers. Soil should be moist but well-drained, and loamy. Wet clay soil will lead to root rot and dry sandy soil will lead to plant wilt. Mix 2 to 3 inches of compost into the soil prior to planting.

• For indoor planting of perennial Asters, prepare seeds by mixing them into some damp sand and keeping the mix in the refrigerator for 30 days prior to planting in starter trays
• For annual Aster seeds, no cold treatment is needed
• Press the Aster seeds into the soil and only lightly cover
• Keep moist and warm for germination
• Harden off the seedlings and transplant out into the garden once frost danger has passed
• Or, in areas with long growing seasons, prepared the garden soil
• Add compost to improve drainage and add nutrients
• Scatter the flower seeds on the surface and lightly cover
• Keep moist for germination
• Thin the plants to the proper spacing depending on the type of Aster
• Pinch back young plants 1 - 2 times to encourage bushier growth

• Watch the Aster plants for any sign of stress
• During dry periods, water the plants regularly
• Mulch around the base of the plant to keep weeds down and help hold in moisture
• Stake taller plants and protect from winds
• In winter, cut the plants back