Recently, the Palo Pinto County Master Gardeners visited a small urban garden that specializes in lettuce and microgreens to be sold at a farmers’ market. Their greenhouse was particularly interesting because the lettuce is grown without soil!
Hydroponics? Well – sort of. This grower uses a system called Aquaponics.
All of the plants are in little slotted pots of non-soil-growing medium, and they float in large flats of water that comes from a fish tank. The grower has about 40 goldfish he feeds. They deposit their droppings that dissolve in the water.
The water tank has a recirculating pump that sends water to the plants. The plants are fertilized by the fish, and the roots clean the water, which is sent back to the fish tank. The product of this complimentary system is delicious, homegrown lettuce.
In the winter, the greenhouse keeps the crop from freezing, and in the summer, the grower uses a shade cloth to prevent overheating. There is a lot of information about Aquaponics on the Internet, and the grower we visited says, “There are as many variations of aquaponics as there are people doing it.” Anyone can try aquaponics at home on a very small scale. One of the master gardeners even said he would try watering (and fertilizing) a small, raised bed in his yard by siphoning water from his outdoor fish pond. Why not?
Texas A&M researcher Dr. Joe Masabani says aquaponics has become popular in Texas because a crop
can be produced with a lot less water, if the water is recirculating. Fish production eliminates the need for fertilizer and produces fish for the table as well. Plus, if there is no soil, one doesn’t have to worry about the PH.
The most cost-effective plants to grow with aquaponics might be herbs, lettuce, kale, watercress and
spinach. Plants sitting in nutrient-rich water with lots of oxygen never rot. When they are harvested, they can be bagged with the roots still on. Or the plants can be trimmed, and the leaves sold with the part left behind regrowing more leaves. They can be kept in the refrigerator to prevent wilting, and will taste like they were just picked.
The farm we visited used an old washing machine to spin the freshly rinsed leaves, drying them before packaging.
Anyone can try aquaponics at home if they have a fish tank, a recirculation pump and a tub for floating their crop.