Gardeners experiment with aquaponics in hopes of sharing what they learn
Not long ago, a small group of Galveston County Master Gardeners began an intriguing experiment in Carbide Park in La Marque. The gardeners took a 300-gallon tank and filled it with about 75 blue gill perch, some koi and goldfish to cultivate what so far has been a successful aquaponic garden.
Aquaponics involves recycling nutrient-rich water from fish tanks into a contained garden, where plants are fertilized with the fish waste. The water is then cleansed with the plants’ roots and the water is returned to the fish tank. At Carbide Park, the tank feeds into six beds of a variety of leafy green plants. The fish help to grow the garden and the plants and herbs help keep the fish alive.
Master Gardener Robin Collins was on vacation visiting Vietnam and Cambodia in 2015 when she viewed several fish-plant setups. She realized it was an economical and sustainable way to grow food in areas that lack good soil or space to have a garden, she said.
“Here in the U.S., at some point in time down the road as the population increases, this untraditional form of gardening could be done on a roof, in a basement or on areas of land that will grow nothing because it is too rocky,” Collins said. “And it is organic. We cannot add chemicals to the water or it will kill the fish. Additionally, we can harvest the fish to eat.”
Aquaponics systems relieve gardeners of weeding. And in such gardens, there aren’t pests to deal with and because the beds are raised, gardeners don’t have to constantly bend. Water use is sharply reduced because everything is recycled back into the tanks. Without chemicals, pesticides or herbicides, there’s no toxic runoff from the garden.
The gardeners feed the fish regular fish food. Fish waste is pumped into a filtering tank, which swirls the water around, and the matter breaks down into smaller particles that easily pass through screens and then into hoses attached to six large bins of soil-less plants. Three of the raised boxes of plants have a continuous stream of water into a porous fired-clay medium; the other three boxes of plants are suspended in floating Styrofoam rafts and the plants’ roots grow in the recycled flowing water, which is aerated to keep it oxygenated.
The fish produce ammonia — fertilizer — that transforms into nitrates, which the plants use as fertilizer. As the water flows, the roots absorb elements from it and the cleansed water is pumped back into the fish tank and the cycle begins again.
“Basically, this is what happens naturally along a stream or river with Mother Nature,” Collins said.
The aquaponics team of more than 15 people in La Marque raised funds to build an open-air covered shelter to house the fish, tanks, pumps and plants.
During the freeze that hit the Texas Gulf Coast in January, the insulated and heated tanks protected the fish and the lettuce, kale, herbs and cabbage continued to thrive.
“We thought the cold weather would be our worst enemy but now realize the heat of our summer may be a bigger challenge than the winter,” she said. The shelter is covered with sun screens that will block out much of the strong rays in the summer.
Because the Master Gardeners program is set up for educational purposes, the team monitors and records everything. Team members log how much fish are fed, any discrepancies they notice, how much the plants are growing and which of the two mediums are better for plant growth.
“In a perfect world, a person could be sustainable with this type of farming,” Collins said. “And because the plants get a super healthy dose of nitrates, they grow more rapidly and larger than traditional soil-based gardening,” she said.
Team members have harvested and eaten the fruits of their labors, Collins said.
“We have sent home a lot of greens with team members and we have had some great salads grown aquaponically,” she said. “But our ultimate goal is to produce a lot of valuable information for Galveston County residents who might be interested in this type of installation at their homes.”