Petunias are one of the most versatile bedding plants available. Originally available only in single varieties of purple and white, petunias are now available in big, ruffled double blossoms or in simple but eye-catching single blooms. The colors range from vivid purple, crimson, burgundy and magenta, to muted shades of pastel yellows, lavenders and pinks. Plant petunia bedding plants in spring, and they will provide plenty of color to your flower bed all summer long.
Purchase petunia bedding plants at a reputable garden center or greenhouse. Choose small petunia plants with healthy, green foliage and plenty of plump buds. Avoid petunias with yellow or pale green leaves, or plants that look spindly or unhealthy.
Choose a sunny spot in your garden. Petunias will do best in full sunlight. Petunias will grow in nearly any well-drained soil.
Prepare the spot by cultivating the soil to a depth of 8 to 10 inches with a hoe or shovel. Mix 2 to 3 inches of rotted manure, compost or peat moss to the top of the soil, and work it in to the soil thoroughly.
Use a trowel to dig a hole for each petunia. The hole should be just deep enough to accommodate the petunia's root ball.
Remove the petunia carefully from its bedding container and plant it in the hole. Tamp the soil firmly around the roots.
Water the petunia bed thoroughly, and keep the soil moist until you see the new growth, which indicates that the petunias have successfully rooted. After that time, petunias will only need to be watered during hot, dry weather. Water at the base of the plant, and avoid wetting the foliage as much as possible. Water petunias during the early part of the day so excess water can evaporate before evening.
Fertilize the petunia bed monthly using a water-soluble fertilizer for flowering plants. Apply the fertilizer according to the directions, and don't over-fertilize, as too much fertilizer can cause green, bushy plants with few blooms.
Pinch off spent blooms so the plants will continue to produce blooms as long as possible. When the petunias begin to look long and leggy in midsummer, prune the plants back to 3 to 4 inches so that new, fresh growth and flowers can develop.