Soil temperature: 70 - 75 degrees fahrenheit
Germination lighting: Dark required
Germination days: 10 Days days
Plant spread: 12 inches
Plant height:  30''
Plant type: Annual
Maturation days: 100 days

IA staple for many gardens Asters come in numerous varieties and we consider these tender perennials for zones 3-8 and are not recommended for extreme heat of zones 9-13.  Start by loosening enriched garden soil down to a 6" depth.  If you are going to direct seed sprinkle them after your last frost and cover with a light dusting of compost or peat to a depth of 1/8".   They should germinate in about 10 days and once a couple of inches thin to 12" spacing. 

If in warmer zones (7-8) it's best to start in pots early and then transplant after your last frost in the spring.  Asters are sensitive to heat and mildew so we like to plant them in a area that has good air flow and that gets late afternoon shade.  While they can be transplanted their roots prefer to not be disturbed when transplanted so it's best to use a compostable peat pot, or peat pellets, when starting early in pots and plant the whole pot instead of removing the seedling when transplanting.

A quick note about Asters and a fungus called Fusarium.  In the same manner how Hollyhock are very susceptible to Rust, Asters are susceptible to a natural soil born fungus called Fusarium.  We recommend you dust your Aster garden area in the spring (after tilling your soil), prior to sowing your seedlings, with dustable sulfur which you can get at any home improvement or garden center.  In zone 7 we dust them again around the first of July just to make sure we don't have any problems with Fusarium during the summer.  Sulfur raises the PH of the surface of soil, which does not kill Fusarium, but makes it difficult for it to replicate and spread.