The Right Place
Full sun is required and almost any type of soil of average fertility, moist. Well-drained. Most asters can be planted from USDA Zones 4 to 8 with some planted in Zone 9. Asters can tolerate cold weather down to -20° to -30° F. This takes in most of the U.S.A.
Planting Nursery Stock
Plant seedlings or divisions in spring. Transplant potted nursery stock anytime during the growing season. Choose an overcast day or plant in the evening so that the sun does not stress the transplant while it copes with transplant shock.
Cultivate the soil down 12 inches. Although established plants do not need any special feeding, a handful of a granular all-purpose, slow-acting fertilizer mixed into the soil at this point will give new transplants a boost their first season. Dig the planting hole about as deep and slightly wider than the root ball or container. Set the plant in the hole so that its crown, where the roots meet the stems, is at soil level. Fill in the hole with soil, firming it gently around plant stems to remove air pockets and water well. Set plants about 2 feet apart to allow for their gradual spread. Spread a layer of mulch on the soil over the root Zone to discourage weeds and maintain soil moisture.
The seed will develop inferior plants to the mother plant. Instead, spreading clumps need dividing after a few years. Dig up in spring when young shoot appear, cut through mass of roots with sharp spade or knife to make chunks of rooted plant with at lease 3 to 5 shoots per clump. Replant the remaining clumps if space is available. The root division will provide identical plant reproduction to the original plant.