My favorite water garden containers are the light-weight, hard plastic plant pots that don’t have drain holes. I suggest at least a 10-15 gallon container, though I’ve actually grown water lilies in coffee cups. (They will produce tiny lily pads but will not bloom.) You can get creative and use just about any type of container as long as it holds water and does not release any toxins when wet!
Place your water garden container in your chosen location. It’s best if it gets plenty of sun! I grow each of my water plants in its own nursery pot with clay soil. One exception is Water Lotus, which is a large water plant. You will need to fill the entire water container with 2/3 clay and then add water to top it off. I plant the lotus tuber directly in the container. I use “Special Kitty” cat litter from Walmart that is 100% natural ground clay – NO additives. (It currently comes in the red bag and is much cheaper than bagged aquatic clay/soil!) For all other plants, fill the water garden container with water about halfway. (Adding several pots of plants will raise the water level!) Then add clay to each nursery pot, soak/rinse it thoroughly, and add the plant. You may have to weigh down the plant roots/tubers/rhizomes with a layer of medium or small rocks on top of the clay soil to keep the plant from floating out of the pot when submerged. Be careful when adding rocks to avoid covering or damaging new growth. Top off your water garden with additional water after all of the plants are in place.
You can grow a single plant in a container, such as a water lily or water lotus, or you can grow several plants in one container, depending on the size of your container, the plants, and the pots they are in. There are various marginal-aquatic plants that will grow well in shallow water, such as Lemon Bacopa, Dwarf Bamboo, Mini Papyrus, Sweet Flag, Venezuelan Poppy, Blue Pickerel Plant, Water Iris, etc. It can take a day to several weeks before the water clears (you might get cloudy water from the cat litter or see green algae bloom after a week or so). In time, your water container will settle. As the water environment becomes balanced with thriving plants, the water will become crystal clear.
Caring for water plants is very easy! Don’t add fertilizer to any of the plants until you see new growth. There are special fertilizer tablets, called Pond Plant Tabs, that are designed for water gardening. One tab can be added to each plant pot by pushing the tablet down into the clay soil until it is completely covered. If you are growing Water Lotus, you will need to add 2-3 tabs in the container. Other than providing a sunny spot (at least 6 hours a day) and fertilizing every month, you need only to add water to compensate for evaporation every few days.
Mosquitoes may be a problem with still water, so consider adding some mosquito fish (Gambusia affinis), known fondly as “minnows”. You can get them at a pet store for relatively cheap. I bought a mating pair and had plenty of additional fish in no time at all! These fish love to eat mosquito larvae! (I do supplement their diet with fish food, too.) Fish will also add movement interest to your water garden.
Raccoons and some frog species may require you to cover your water garden at night to prevent these night creatures from getting into the container to eat the fish or lay eggs. I say that from experience! Raccoons love to eat fish and will tear up a beautiful water garden to eat every last one! Frogs love to lay their eggs in water containers. That typically would not be a problem, but the invasive Cuban Tree Frog tadpoles found in Florida will actually eat some water plants! Therefore, covering the containers at night might be a necessity … well worth that little extra effort!
I can honestly say that water gardening is the easiest type of gardening that I do! I have large and small water containers and the water plants thrive and delight me during the long, hot dog days of summer when everything else is looking tired and wilted. No garden is complete without a water garden!
The “Ponds and Water Gardening Forum” here on ATP is a good resource for additional information, and so are the websites listed below: