These porch-step containers begin with bright pink and yellow zinnias. Cooler “filler” flowers, such as purple verbenas and blue calibrachoas are added to create contrast with texture and color. Opt for inexpensive plastic planters that are weatherproof and easy to move around. Grouping them in a tight space creates a homey, mini-garden vibe. Plus, when placed side by side, all of the colors intensify.