The best tips for planting aster seeds concern selection, timing, and location. Growing aster is easy in most climates, as the flower is relatively hardy and does not require any specific soil or light conditions. Gardeners can get more out of their growing experience by taking a few moments to plan out when they will begin, where they will plant, and whether they want the resulting blooms to take on a particular shape, pattern, or organization.
Most of the time, aster seeds will grow wherever they are strewn. Scattering asters across a lawn or open field will usually result in a summertime bloom, regardless of whether a gardener ever tends to the plants. Intentionality often leads to a better growing experience, however, and can go along way in landscape planning. Gardeners who plan their growing experience usually get more out of it than those who take a more haphazard approach.
The first thing a gardener must do is determine what sort of aster flower he or she wants to grow. Asters come in many different varieties. The genus Aster, which carries the scientific name Asteraceae, includes at least 25 distinct species. All are similar and most will grow nearly anywhere, but they have different sizes, coloring, and bloom periods. Gardeners who are serious about cultivating aster seeds would be wise to research the species that grow natively in their geographic area, are optimized for their particular soil or other habitat conditions, or have desirable colors and stem heights.
Once the seeds have been selected, timing becomes quite important. Asters have a very quick germination period, often sprouting within a week to ten days after initial planting. Seeds started indoors can usually be planted any time, but outside, gardeners should wait until after the last frost before beginning. A late frost is often deadly to young aster seed sprouts.
Aster seeds should be planted under a very thin layer of soil, usually no more than a ¼ inch (about 6 mm) deep, in a location with full sun exposure. Adding fertilizer or using specially-formulated bloom soil will help the seeds begin to grow, and can lead to stronger, fuller flowers later in the season. Many gardeners add fertilizer once buds appear, but fertilizing at the seed stage often gives an even greater advantage, as it allows the seeds to store and retain necessary nutrients from the very start.
Soil should be moistened at first, but not saturated. Asters generally do much better in droughts than floods, and too much water can stunt their germination and growth. Caring for aster plants requires regular water checks and proper drainage, particularly in the early stages of germination.
Many gardeners elect to begin aster seeds in indoor pots as a means of plant control. Young sprouts can be nurtured in a temperature-controlled environment, which helps build sturdy foundations. This method also gives gardeners greater control over eventual garden layout.
If aster seeds are meant to fill in empty patches of yard or add color to an un-landscaped area, random planting can be desirable. Gardeners often sow aster seeds as a part of planned garden design, however, which requires more careful spacing between plants and intentional color organization. Beginning indoors allows gardeners time to observe which flowers have bloomed, as well as to take stock of their individual characteristics. Yard transplant can be much more intentional when seedlings are placed from the start. Aster seedlings that have sprouted outdoors can sometimes be moved or rearranged mid-season, but this is often much harder.