As you drag your containers out from last year, check the soil. If the soil is two years old or older, it is time to freshen it up. Take at least half the soil out of the container and add new potting soil. Do not use top soil. Top soil is heavy and does not drain well in containers.
Potting soil is a good balanced mixture made specifically for container gardens. Make sure you add a time released fertilizer as you put your plants in their new home. Time released fertilizer is perfect for containers and needs to be added about every 60 days during the growing season.