Buy seeds or seedlings from a local nursery or from a mail-order catalog.
Choose a site for annual baby's breath that gets full sun. If you live in the South, your annual baby's breath will benefit from some afternoon shade. The site also should have excellent drainage.
Sow seeds directly in the soil in fall where winters are mild - Zones 8 and warmer of the U.S.D.A. Plant Hardiness Zone Map. Otherwise, plant seeds directly outdoors in early spring after soil thaws.
Plant seedlings, if available, outdoors in late fall in Zones 8 and warmer, or plant them in spring a month before your region's last annual frost date in colder climates.
Plant about 8 inches apart. Baby's breath blooms best if it's a little crowded.
Let it be. Once established, baby's breath needs little care. Its flowers don't need to be deadheaded and it thrives on minimal water and fertilizer.
Discard the plants once they begin to get ratty from the heat or are felled by frost in autumn.