Care of petunias includes regular watering and as much sunlight as possible to promote multiple blooms. Spreading ground cover petunias are pickiest about water, weekly waterings should be included in the care of petunias. While petunias will grow in a partially shaded location, a fuller and more abundant bloom is produced in full sun. Soil prepared before planting petunias should have well-composted organic matter worked in. Care of petunias will include regular fertilization with a balanced, water soluble fertilizer designed for blooming plants. As they are heavy feeders, petunias care will also include weekly feedings. Proper light, water and fertilization when caring for petunias will ensure a long season of beautiful blooms. Proper petunia care involves removing spent blooms and the seeds they may produce. When deadheading the growing petunias, remove the base of the flower to include seed removal. Petunias allowed to go to seed will slow or stop blooming.
Read more at Gardening Know How: Caring For Petunias: How To Grow Petunias https://www.gardeningknowhow.com/ornamental/flowers/petunia/petunia-care.htm