A container with a capacity of 15-25 gallons is practical. Many commercial containers are available or you might consider things like small kiddie pools, horse watering troughs, lined whiskey barrels or even old bathtubs. Remember that water weighs about 8 pounds per gallon, so be sure the location of your container will be able to hold the weight. Locate the garden so it receives a minimum of six hours of sun a day. Most aquatic plants need full sun. Some of the bog plants can survive in less. Less than six hours will decrease the blooming potential of aquatic plants. Choose containers with interiors that are dark in color. Dark green, charcoal or black colors are suggested because they give the container an impression of greater depth, discourage algae growth, and make algae less obvious when it is present. Stones and slate can be added for interest, but keep in mind that choosing dark colored rock will help discourage algae.
Planting the Garden
Plants used in small aquatic gardens are grown in separate pots and then these pots are placed into the water-filled container. Heavy, clay garden soil is used as a potting media. After the plant is potted, top the soil with a 1/2 to 3/4 inch layer of pea gravel to help keep the soil in place. Don't use a commercial potting soil mix or any type of soil mix containing fertilizer. Fill the tub with water and set your plants in place. Some aquatics prefer to be placed at certain depths in the water.
Adjust the depth of your plants by placing bricks under the pot so the crown of the plant is at the preferred depth. About 50 - 60% of the water surface should be covered with plant material. Take note of the type of water used to fill your container. City water supplies are commonly treated with chlorine. It is a good idea to let the tub sit for 24-48 hours before adding plants to allow the chlorine to evaporate. Many city water supplies are now using chloramine, a more stable form of chlorine. If this is the case, you might want to purchase a product to remove the chlorine. These are available from garden centers and pond supply dealers. Don't use water from a water softener and don't add chemicals to the water.
A tub garden is a miniature ecosystem of plants, water and fish. This system must come into balance which means that the plant and animal life are able to hold the algae growth in check. It will take approximately 3-4 weeks for this to occur. Two weeks after you set up the garden, the water will turn cloudy with algae. In another week or so, the water will clear and remain that way. The aquatic plants and animals keep the algae under control by reducing the sunlight entering the water and competing with the algae for nutrients in the water.
Plants for the Aquatic Garden
Aquatic gardens need a mix of plants to attain a balanced system. These plants can be a combination of emergent, submerged and floaters.
These are also called oxygenators and help clean the water and supply oxygen. Some to consider include:
Wild Celery (Vallisneria sp.) Ribbon-like, translucent, pale-green leaves. Will grow in shade, part-shade and sun in water that is 6– 24 inchesdeep.
Fanwort (Cabomba canadensis) Bright green fan like foliage. Fish tend to use them to spawn and fry will find shelter in the leaves. Will grow in sun to shade in water that is 6– 12 inches deep.
Anacharis (Egeria densa) Whorls of deep green leaves with occasional white flowers on the surface. Most common oxygenator. Grows in water 12 inches – 10 feet deep.
These plans are potted and placed from 3 – 6 inches below the surface of the water. Some to consider are:
Arrowheads (Sagittaria sp.) Attractive, green arrowhead shaped leaves. White blooms in the summer. Grows from 12 – 48 inchestall. Tolerates sun to part shade.
Blue Flag Iris (Iris versicolor) Mixed blue flowers in June with grass like foliage. Grows from 24 –30 inches tall and will tolerate full sun to part shade.
Dwarf Papyrus (Cyperus isocladus) Green grass like foliage with "starburst like" flowerheads that turn brown in the fall. Grows 12 – 18 inchestall and tolerates sun to part shade.
Water Blue Bells (Ruellia brittoniana) Green grass like foliage growing to 24" –48" tall. Blue flowers in summer resembling petunias. Tolerates sun to part shade.
Cork Screw Rush (Juncus effusus) Interesting twisted and curled stems. Grows to 24" tall and tolerates full sun to part shade.
Lotus and Water Lilies
Several of the smaller hardy and tropical water lilies do well in containers and can add both color and fragrance. Lotus are also a dramatic addition to water gardens. Both water lilies and lotus prefer full sun.
'Joanne Pring'- A hardy miniature pink water lily with green leaves and deep edge
'Tetragona'- A hardy miniature white water lily with freckled leaves
'Helvola'- A hardy miniature yellow water lily with freckled leaves
'Hilary'- A tropical day blooming pink water lily with green leaves
'Red Flare'- A tropical night blooming red water lily with maroon leaves
'Momo Botan' Lotus Grows to a height of 24" and offers rose blooms July – September
'Wan-er Hong' Lotus Grows to a height of 12" and offers white blooms June – September
These plants add a finishing touch to the water surface. Some plants to consider are:
Giant Velvet Leaf (Salvinia longifolia) Unusual floating fern with pale green round hairy leaves.
Water Hyacinth (Eichhornia crassipes) Popular floater with long, trailing roots, balloon like petioles and spikes of pale lavender flowers.
Water Lettuce (Pistia stratiotes) Velvet, blue green leaves forming a rosette of foliage that looks like leaf lettuce.
Fish and Snails for Water Gardens
Pond creatures can be added to your water container for added interest and to help in maintaining the ecosystem balance. Several small snails are very helpful as they eat algae, fish waste, and decaying organic matter. Fish such as mollies, guppies, platys or gambezi are good choices. They do well in the variable water temperatures of a small patio pond plus they eat mosquitoes. Larger containers of 20 gallons or more can handle one to two goldfish.
Overwintering the Garden
Plants in small water gardens will need to be brought in for the winter. Potted plants can be lifted out of the water and stored in water filled tubs in a cool, dark basement. They will go dormant and can be brought back to the garden in the spring after the weather warms. Floaters may be overwintered indoors in aquariums where there is high light. It may be best to handle these as annuals. Buying new plants each season. Any fish will have to be brought inside for the winter.