An interesting reserve crop for aquaponics, which rapidly fills in for missing plants in plant positions in your grow beds or floating raft system, is the edible morning glory or “water spinach”. This is a very popular food in the Far East. Edible morning glory or “water spinach” will grow just by slipping cuttings of it into your aquaponic system. Its botanical name is Ipomoea aquatica, (eep-oh-MEE-uh a-KWA-ti-ka, water loving Morning Glory.) It’s a native of China called “water spinach.” DON’T CONFUSE IT WITH NORMAL GARDEN MORNING GLORY, WHICH IS POISONOUS. If you do find it in the USA, depending where you live, you’re expected to report it because it can be invasive. Where fresh water doesn’t freeze, such as Florida, it is colonizing the waterways. In northern areas, winter keeps it from spreading. If you are growing it in an aquaponic system, it is difficult for it to spread, since it is contained by the tanks.
There are two versions of I. aquatica, narrow leaf and wide leaf, both are edible. And actually they come in two colors. The “green” version has green stems and white flowers with red throats. The “red” version has purple-tinged stems with pink or lilac flowers with red throats. They both grow only in water, or very damp soil, when not growing in aquaponics systems. The vines, with milky sap, can reach up to 70-feet long (the state of Florida says only nine feet.) Shoots and leaves are the edible parts of your crop. You will not find this plant growing in dry areas.
However, you will be growing this crop to eat as a stir-fry vegetable in an aquaponics system, and will not be likely to see the flowers. The shoots make up a cut and come again crop, however, as long as you leave an inch or so of stalk and leaf on the plant. They grow very rapidly in aquaponics and can cover your grow bed or floating raft system with a crop of edible shoots in as little as three weeks. Edible morning glory or ‘water spinach’ is a very popular vegetable in Thai and Chinese restaurants, where you would find a market for your crop, no doubt.
Edible morning glory or “water spinach” is raised as a vegetable in Florida under strict conditions and only for out-of-state sale. It is also grown commercially in Texas, Hawaii and California. In the United States it is found in the wild in (mostly central west) Florida, Hawaii and Puerto Rico. I first came across it growing luxuriantly in the aquaponics system at the University of the Virgin Islands, though I had eaten it innumerable times when living in China and Thailand.
It can be eaten raw when found in wholesome water. The water in your aquaponics system should be wholesome, if you have paid attention to water quality and hygiene around the system. Fish are cold-blooded, so fish farm waste water does not carry bugs that are harmful to humans (who are warm-blooded), unless humans have introduced them from elsewhere. Otherwise, edible morning glory or “water spinach” should be cooked. The leaves are 48% carbohydrates, 24% proteins, 13% ash. They are rich in minerals and a good source of vitamins A, C and E. That is a better nutritional profile than a lot of other green leafy vegetables. It is a major food crop and vegetable in its native lands. The roots are sometimes eaten. Like other members of this family of plants, these edible morning glory roots are toxic to horses.