Some plants require special care and attention to seed and propagate. Petunias are self-seeding annuals, meaning they will produce and disperse seeds on their own. However, knowledge of ideal petunia growing conditions can still help increase the likelihood of healthy propagation.
A healthy self-seeding petunia will produce seeds within the centre of the flower. Petunias blossom and seed in summer or early autumn. These seeds will fall off near the flower, creating additional petunia blossoms next growing season.
Make sure your garden has nutrient-rich, but well-drained soil. Overly moist soil is not conducive to petunia seeding.
Petunias require full sun and moderate water. Plant your petunias away from overbearing shrubs or other shady objects. Your flowerbed should be moist to the touch, but not soggy or wet. With adequate sun and water, your petunias will propagate on their own.