Of all the varieties of flowering annuals, petunias are among the most popular. The ease in growing them make petunias favorite choices for gardeners wanting to spruce up their gardens with color. Petunias come in hundreds of varieties, and the colors are almost endless. The four categories of petunias are grandiflora, being most common with its large flowers; multiflora, having smaller flowers and compact growth; milliflora, having miniature foliage and flowers; and groundcover petunias, having a spreading habit. Adding petunias to your garden will be a welcome and colorful addition.
Wait until the spring to plant petunias in the garden, when cold weather has left your region. Do not plant petunias outside if frost or freezes are possible; the plants will not survive.
Plant the petunias in an area that receives at least four to five hours of full sunlight each day to get the best blooms. Petunias will tolerate partial shade but will not bloom as well.
Clear the planting site of weeds or other growth before placing the petunias in the ground. If herbicides are used, wait several weeks before planting to allow sufficient time for the herbicide to wash from the soil.
Amend the planting area with organic material, working compost, manure or peat into the existing soil. Use a shovel or planting fork to work the organic material into the first foot of soil.
Add a 12-12-12 fertilizer to the soil and work it in at a rate of 2 pounds for every 100 square feet of planting area.
Dig a hole that is a little larger than the root ball and no deeper. Remove the petunia from its container, being careful with the roots, place in the hole and pack the soil around it.
Space petunia plants grown in full sunshine 12 inches apart and space petunia plants grown in partial sunshine 8 to 10 inches apart.
Water the petunias in well after planting and continue with a schedule of watering of once to twice per week, depending on your regional temperatures. Water plants more frequently if your weather is extremely hot and dry.
Fertilize the petunias weekly with a 20-20-20, water-soluble fertilizer, following the manufacturer's instructions. Spray the entire plant with fertilizer.