To set up a backyard container water garden, prepare a commercial container, lined whiskey barrel, horse watering trough or other container capable of holding 15 to 25 gallons of water, and place it in a location with access to at least six hours of sunlight daily. Grow plants in separate pots before transferring them to the water-filled container. After filling the container with water, leave it for up to 48 hours before placing the plants to let the chlorine evaporate.
Choose a variety of plants to create a balanced water garden. Anacharis, fanwort and wild celery are excellent submerged plants that help maintain clean water and provide oxygen supply.
Arrowheads, blue flag iris, dwarf papyrus and water blue bells are good choices for emergent plants, which should be potted and positioned 3 to 6 inches beneath the water surface. Also, add floaters, such as water lettuce, water hyacinth and giant velvet leaf.
Add fish, such as platys, guppies and mollies, and small snails, which consume rotten organic matter, fish waste and algae, to your container water garden for a balanced ecosystem. Include one or two goldfish if your container holds at least 20 gallons of water. When winter comes, bring small plants indoors, transfer potted plants to water-filled tubs, and store the tubs in the basement. Place floaters in aquariums with plenty of light.