Plant Parenthood: What to expect from a water-based garden
HOUGHTON — There are a lot of reasons to consider growing indoors if you live in the Upper Peninsula. Short summers and increasinly unpredictable storms make growing almost anything outside a risky endeavor. But some reasons aren’t exclusive to the U.P., either.
“It’s easy to keep diseases down,” Lexi Steve said.
Steve is a student at Michigan Tech and a resident at the Sustainability Demonstration House, where she recently assembled a hydroponic grow system along side the aquaponic system started last year.
“We use very little water,” said Rose Turner, another student who has overseen the aquaponic system.
While both systems are based on and filled with water, it is the same water cycled over and over. Growers report using as little as 1/20 the water used to grow a similar crop in soil. Only a little needs to be added to account for evaporation and splashing.
Both growing systems are also excellent at delivering nutrients to plants and encouraging fast growth, almost too fast, according to Turner, whose plants struggled under their own weight this spring.
The root of the differences between the systems is the inclusion of fish in aquaponics, whose waste is converted by bacteria in the grow bed into food for the plants. In hydroponics, plant food is added directly to the water by the gardener.
In fact, the fish in the aquaponic system are among the reasons Steve launched her hydroponic system. Over the summer, she had to clean the fish’s tank.
“I never wanted to do that again,” she said.
Steve’s hydroponic system is built in a vertical style, good for taking advantage of natural light from the large windows in the SDH. The various greens are placed in small pockets and rooted in rock wool. The nutrient-rich water is periodically washed over the base of the wool by a pump on a timer.
Turner’s aquaponic system utilizes a planting bed which slowly fills with water continuously pumped into the bed. The bed is then periodically drained using a bell siphon.
One advantage of the bed-style grow system is the ability to plant a wide variety of plants. The students recently planted an avacado pit which has begun to grow.
“We can actually see the roots,” Steve said.
Both systems are still works in progress.
Steve is still finishing routing the water in her system to insure proper saturation, and is still calculating the correct amount of plant food solution to add to the water as the plants mature.
Turner is fine-tuning the piping in the aquaponic system to prevent water loss due to splashing and increase reliability of the flush-and-drain cycle of the bed. Because of the way a bell siphon functions, the bed can get suspended in a flooded state if the pump is pushing too much water into it.
This happened over the summer while students were gone, which quickly destabilized the system and hurt some of the plants and fish. A valve on the bed’s input has solved the issue, but Turner still keeps a close eye on it.
She’s also planning to add more plant and animal species to help maintain the ecosystem. Plecostomus, also known as sucker fish, would help keep the fish tank walls clean. Duck weed can be grown in the tank and will help feed the fish.