How do you plant petunias outside?

When the plants have three leaves, you can plant them outside. It’s best to buy transplants and plant them in light, well-drained soil in full sun after the last spring frost. (See your local frost dates.) Petunias can grow in partial shade, but they will have fewer flowers.Click to see full answer. Considering this, what month is best to plant petunias? How to plant Petunias: Petunias can be planted outside from early May, once all danger of frost has passed. Use freshly prepared soil or a balance potting compost when planting. To start with, water every three to five days, take care not to get the foliage wet when watering as this can damage the plant and promote disease. Subsequently, question is, how deep do petunias need to be planted? Planting Recommendations Organic matter such as peat moss, aged manure or compost should be applied to a depth of 2 or 3 inches and worked thoroughly into the soil to a depth of 8 to 10 inches. The site should also drain well, as petunias do poorly in soil that is too wet. Also to know is, when can I put petunias outside? Wait until all danger of frost is past before planting your petunias outdoors. Petunias repeat bloom throughout the summer. Some varieties will require frequent deadheading and some stem pruning to continue setting flower buds.Do petunias spread?Groundcover or “spreading” petunias are only about six inches tall, but spread so rapidly that they cover a huge area over one growing season, provided they’re watered and fertilized frequently. “Wave” petunias are a common type of spreading petunia. A Grandiflora petunia flower with white picotee edge.