Growing aquatic plants is just a different form of gardening than most people are used to. There are many similarities to water gardens and soil gardens, such as how much light they need and the types of nutrients needed to keep the plants growing healthy. Although water gardens can be a challenge, aquatic plants are a beautiful and relaxing part of your landscape when taken care of properly.
Purchase enough containers for your plants. Containers should be between 6 and 20 inches in diameter, depending on the size of your plant. Larger containers should be at least 10 inches deep. Cut burlap to lay in the bottom of the containers so the soil does not leak out the drain holes.
Fill the container two-thirds of the way with a damp heavy loam soil. Push fertilizer tabs to about an inch off the bottom with your finger. Place the recommended amount of tabs in each container according to the directions for the size container and type of plant you will be growing.
Place the plant on top of the soil and fill in around the roots. Different plants are to be planted in different ways.
Hardy water lilies have a rhizome, which should be planted at a 45-degree angle from the top to bottom. The growing point of the rhizome, which looks like a small bud, should be toward the side of pot. Cover with soil so the bud is just above the soil. These plants can be placed in the pond when the water temperature reaches 50 degrees Fahrenheit or above.
Plant tropical water lilies and lotus in the center of the pot. The rhizomes should be 2 to 4 inches deep with the growing points just above the soil level. Lotus rhizomes are easily damaged and should be handled very gently. Lotus can be placed in the pond at temperatures above 50 F and tropical lilies cannot go in the water until the temperature reaches at least 70 F.
Plant submerged plants with six to 10 plants per pot in the same fashion as the larger plants. If your pond will contain fish, you might want to put a cage around these plants as the fish tend to eat them. These plants put oxygen in the pond, so don't leave them out.
Cover the soil with about 2 inches of gravel. This will keep the soil from clouding the water and weigh them down a bit from wind. If you have fish in the pond, use a larger-sized gravel or stones, as the fish may suck the small gravel in their mouth and get it stuck.
Water the plants well so there will be less soil spillage when you lower them into the pond.
Add bricks to the deep areas of the pond to hold the containers at an appropriate depth. Flowers and leaves of lilies and lotus should be above the waters surface. They can be lowered as they grow larger.
Lower the containers very slowly to the location you have chosen. Lilies should be 6 to 12 inches below the surface and lotus about 4 inches. Submerged plants can be at any level, commonly placed on the bottom of the pond. Floating plants can just be placed in the pond when the water temperature is around 70 F and allowed to float.