What Is the Habitat of a Petunia?

Climate Conditions

• Areas that receive six or more hours of sunlight daily help petunias produce the most flowers, but they can tolerate light shade if you don't mind fewer blooms. Petunias don't tolerate cold and a frost will kill the plants. It's best to plant them outside after the soil temperature is above 60 degrees Fahrenheit and all frost danger is past. Summer heat may weaken the plants or stop them from blooming, but they usually survive and will send up a new flush of bloom after the heat wave passes if provided with water and a timely pruning.

Soil Needs

• Petunias tolerate almost any type of soil as long as it is well drained and doesn't become wet or waterlogged easily. Best growth occurs when the soil pH is between 6.0 and 7.0, which you can determine with a soil testing kit. Tilling a 2-inch layer of compost into the top 6 inches of soil improves drainage. Although petunias can grow in poor soil, an application of fertilizer before you plant them provides nutrients that can increase plant health and bloom. Use ½ pound of 5-10-5 fertilizer over every 25 square feet of bed and work it into the top 6 inches of soil along with the compost.

Location Ideas

• Although garden beds provide a suitable habitat for petunias, they also grow well in containers. Milliflora varieties produce more flowers although they are smaller, which can provide a mound of color in hanging baskets and pots. Trailing petunia varieties are best suited to hanging baskets and window boxes where they can trail over the edge. These varieties also work well as a flowering groundcover in garden beds. If you don't have a bed available with suitable drainage or soil, consider planting petunias in a raised garden bed. Raised beds usually drain better than traditional garden beds.

Care Tips

• Regular watering and pruning results in the most compact plants and optimum flowering. Petunias require about 1 inch of water weekly, which is enough to moisten the top 6 to 8 inches of soil. Weekly irrigation that wets the soil to the required depth encourages deep root growth. Covering the soil with a 2-inch layer of mulch helps retain suitable moisture and prevents weeds. Petunias can become leggy at midseason. Cutting them back by half their height forces a new flush of growth and flower production. Pinching off the spent blooms can result in more flowers.