The tradition of water gardening stretches back to the ancient world. There were ancient water gardens in Babylon, Egypt and Rome. Today, when you build a water garden in a barrel or a large container, you tap into the ancient desire to shape a landscape to your whims and to have water where there is none. Tiny water gardens in bowls are good places to grow miniature plants such as water lilies.
Buy a waterproof container such as a plastic or Fiberglas pot. Terracotta, cement or clay containers are porous and may sweat water through their wall surfaces. If you choose a half-barrel such as a whiskey or wine barrel, purchase a barrel liner. The barrel liner is watertight and will keep the preservatives in the barrel from leaching into the water.
Place a plastic plug into the bottom of the container to close the drain hole. Some plastic or Fiberglas pots do not come with drain holes. If you use a plastic plug, secure it in place with silicone caulk. Let the caulk dry before continuing with the project.
Fill the container with water. Allow the water to sit for 48 hours so chemicals such as chlorine in the water can dissipate.
Purchase miniature water lilies based on the depth of your container. Good lilies for containers are Burgundy Princess, Rustica Sioux or Berit Strawn. These lilies will thrive in shallow water and will not take up much space in a container.
Fill an aquatic grow basket with aquatic potting soil. Place the tuber of the water lily into the basket so the tuber rests on the top of the soil. Cover the tuber and the soil with pea gravel so just the top of the tuber sticks out above the gravel.
Place the aquatic basket in the centre of the water-filled container. If the container is too deep for the lily's growing height, place bricks in the centre of the container and put the aquatic basket on top of the bricks to raise the lily to the correct height. Lilies require little fertilisation and care to produce foliage and flowers.
Overwinter hardy lilies by trimming away the foliage. The tuber will survive inside the container in the water. Remove tropical lilies and overwinter them by burying them in a bucket of damp sand and placing them in a dark, heated location such as a basement.