Petunias are one of the best summer flowering annuals for massed display, and they also look good in pots and hanging baskets. The color range is huge, with varieties available in every color except orange. You can expect blooms throughout the summer and into autumn if faded flowers are removed regularly. Plants quickly grow to a height of 10-16 inches. Petunias can be used as cut flowers, but they look their best in garden displays.
The very fine seeds are hard to handle, and you'll have better luck starting them indoors. Cover with a dusting of soil and water from the bottom of the pot to avoid dislodging seeds. When seedlings are 1-2 inches tall they can be transplanted outdoors at intervals of six to eight inches in soil that has been enriched with compost or manure. Pinch out the growing tips when they reach a height of 3-4 inches to encourage bushy growth. Water regularly to establish, and thereafter wait until the soil dries out to water. Overwatering will cause foliage to yellow and the plants will eventually die. Overfertilizing will result in an abundance of foliage with few flowers. Limit supplemental feedings to one or two during the growing season. After the first flowering flush, cut the plants back to encourage a second blooming.