Alpine Aster
Aster alpinus
Plant out 1 week before your last spring frost. Space plants 12 in (30 cm) apart.
Photo: Robert Flogaus-Faust, CC BY 4.0 · source
When to plant
Timed from your frost dates, so it holds wherever you garden. Give yours and every step below becomes a date.
Optimal Transplant (Spring)
From a plantRecommended from a plant- Plant out1 week before your last spring frost
- First harvestsummer, once established
Optimal Transplant (Fall)
From a plant- Plant outabout 20 weeks before your first fall frost
- First harvestsummer, once established
Optimal Indoor Start
From seedRecommended from seed- Start indoors9 weeks before your last spring frost
- Begin hardening off2 weeks before your last spring frost
- Plant out1 week before your last spring frost
- First harvestsummer, once established
Optimal Transplant
From seed- Plant out1 week before your last spring frost
- First harvestsummer, once established
Optimal Direct Sow (Fall)
From seed- Sow outdoorsabout 20 weeks before your first fall frost
- First harvestsummer, once established
Optimal Spring Direct Sow
From seed- Sow outdoorsaround your last spring frost
- First harvestsummer, once established
Growing alpine aster
- Spacing in the row
- 12 in (30 cm)
- Between rows
- 12 in (30 cm)
- Planting depth
- 1/8 inch
- Sun
- Full Sun to Part Shade
- Soil
- Well-drained, sandy loam to average garden soil
- Germination
- 14-28 days at 60-70°F
- Harvest season
- Summer
- Mature height
- 8-12 inches
- Hardy to
- USDA zone 4
- Life cycle
- Perennial
Sow seeds lightly covered, or cold stratify for improved germination. Keep consistently moist.
Watering. Water regularly to maintain consistent soil moisture, especially during dry periods. Established plants are moderately drought tolerant.
Neighbours
The companion chart →Grows well beside
Coneflower- Salvia
Phlox- Bellflower
Yarrow- Delphinium
Feeding
- Seedlings
- Light liquid feed at half strength after true leaves appear.
- Growing
- Balanced slow-release granular fertilizer in early spring.
- Flowering and fruiting
- Balanced granular fertilizer or a bloom-boosting liquid feed if growth is weak.
- How often
- Once a year, in early spring, for established plants. Seedlings as needed.
- Note
- Avoid over-fertilization, which can lead to leggy growth and reduced flowering. Prioritize soil health.
Your alpine aster, planned to the day.
Canopy turns these timings into dates from your own frost data, places every plant at its spacing on your garden map, and tracks it all the way to harvest.