Spring is the best time of year to get a new garden started in Pittsburgh. The area's cold winters make fall planting challenging, because new plants aren't adapted to their planting environment by winter. Plant annual and perennial flowers on a cloudy day--heat stresses out young plants--and draw inspiration from Pittsburgh's Botanical Garden, your neighbor's gardens or design magazines. Planting flowers from transplants is much easier than growing flowers from seed, and allows Pittsburgh gardeners to enjoy an instant flower bed.
Select flowers that will grow and thrive in Pittsburgh by visiting local garden centers. Choose either annual or perennial flowers designed to grow in USDA hardiness zones 5b to 6b, where Pittsburgh is located. Avoid plants with many wilted flowers or yellowing or bruised leaves. Inspect the root system of the plant by examining its stem and looking at the bottom of the container. If roots are coming out of the bottom, don't buy the plant because it's root bound and the tangled roots will be messy to unwind before planting.
Prepare the garden bed for planting by turning the soil over with a shovel to aerate it. Break apart soil clods and loosen the top 6 to 12 inches of soil; this makes it easier to dig holes for your plants. Remove any weeds growing in the garden bed and pull out rocks, sticks or other debris before planting.
Dig one hole for each flower, making the holes twice as wide as the plant's root ball. Follow the spacing recommendations on the plant tag, which indicate how much space to leave between flowers and how much light each type of flower needs. Place full sun flowers in full sun and those that require full to part shade in their preferred environments to have the healthiest garden.
Pull the flowers from their containers. Massage the root ball between your fingers to loosen it. Then place one flower in each prepared hole.
Hold the flower vertical with your hand. Gently firm soil around the roots and stem to plant it. Plant all flowers in this manner.
Water the newly planted flowers until the ground becomes saturated.