Wave petunias need lots of everything. They love direct hot sunlight and as a result, they love to be watered. During the summer, your Wave Petunias will need to be watered once or twice daily depending on the temperature outside. When it gets really hot, 90 degrees, or more, they may need even more water. Wave Petunias also love to be fertilized. We suggest that you use the constant feeding ratio when fertilizing.