Line 10-inch-diameter potting containers with burlap and fill them with regular soil from the garden. Don't use potting mix, as this is too light and dissolves or floats in the water.
Mix five to six aquatic fertilizer pellets into each potting container.
Trim any dead leaves off the baby plants and any woodier roots (thicker with less flexibility) using the pruning shears.
Make a hole in the soil at the edge of the potting container, big enough for the tuber and roots of the lily. Plant the lilies with the tuber of the plant pointing inward to the center of the pot, covering the roots and tuber of the plant with soil. This encourages the lilies to spread their roots evenly in the container.
Fold over any excess burlap onto the top soil of the potting container. Cover the top of the container with pebbles to prevent the burlap and soil from floating in the water.
Drench the potting containers with water so that the soil is all wet. Gently lower the potting containers into the garden pond or water garden. The water may become a little cloudy as some soil will inevitably mix with the water. Don't worry if the pads of the baby lilies aren't quite on the surface of the water -- they'll grow to the appropriate height to float on the water surface.