Hydroponic and aquaponic vegetables are becoming more popular with growers and consumers alike. Consumers enjoy fresh, organic produce and growers appreciate the potential high-yield of hydroponic systems. If you are interested in trying your hand at setting up a system, do not be intimidated. I bet you already have some practice at the science behind the system. If you have kept rooted cuttings in a jar of water on your kitchen window, you have used hydroponics.
Hydroponics is simply the science of growing plants without soil. Growing produce in this way relies on plants getting the nutrients they need as well as the correct light and temperature. There are four main benefits of growing your produce in a hydroponic system: efficiency, water and space conservation, and high yields.
Efficiency is the main principle behind a hydroponic garden. The system is designed so that you only use what the plants need to grow. Not only efficient, but it is also a green system. Because there is no soil disturbance, there is no erosion and using hydroponic nutrients ensures there are no chemical residues on the plants.
Water conservation is another aspect of hydroponics’ green design and it is a tremendous benefit to all gardeners, but especially to those trying to grow in dry climates. Hydroponic gardening uses as little as 1/10th the amount of water that is used in traditional gardening. Water waste is greatly minimized by applying water directly to plant roots. Space conservation is a plus for urban gardeners or others who are trying to grow garden-fresh food with limited yard space. A hydroponic system can even be set up indoors under artificial lights for those with no land access.
The yield of produce you can get from a good hydroponic system is nothing short of amazing. One reason for this is that the plant root systems are much smaller so plants can be spaced close together. The average yield for hydroponic tomato farmers is 18 times more per acre than conventional tomato farming methods. Another boost to yields is that a hydroponic system can produce year-round, unaffected by seasons and unfavorable weather conditions.
The main drawback to hydroponic gardening is the cost. Upfront and operational costs are higher than for normal gardens.
Hydroponic gardens can be as small or large as you need them to be. You can scale these instructions up or down to meet your needs.
Location is the first thing you need to decide when you are building a hydroponic system. Choose a place with good air circulation. If your system is indoors, place it in indirect sunlight in an area that maintains a temperature between 55-70 degrees Fahrenheit. You will need a water source and an electrical outlet close by.
Small Hydroponic Garden Supply List:
- Fish aquarium, any size
- Styrofoam, 1 inch thick, to fit inside aquarium
- Two 4-foot fluorescent light bulbs
- aerator for aquarium
- hydroponic fertilizer
- cotton, or other flexible fabric
Fill the aquarium with water. Let this water sit in the aquarium for 24 hours in order to allow the chlorine to dissipate. Cut plant holes in the styrofoam. The holes should be just large enough to accommodate the root systems of the plants you have chosen. Drill additional smaller holes in the styrofoam for aeration.
Install the lights 3-4 inches above your plants. This light will support leafy vegetables such as lettuce, spinach, and herbs.
Thread the plant roots through the plant holes. Secure the stems by packing cotton or other fabric around them. Submerge the roots in water.
Install the aerator. This will oxygenate the roots by pumping air bubbles into the water.
Fertilize small plants every other week with the hydroponic fertilizer. Increase the frequency of fertilizing to once a week as the plants mature. Add water every other day to top up the aquarium. Do not add fertilizer on the day you add water. This can burn the roots of your plants.
Aquaponics is similar to hydroponics in that it does not use soil to grow produce. The difference is that fish are a key component in the aquaponic system. The food eaten by the fish is released as metabolites. The metabolites are metabolized by bacteria, and the resulting product is nourishment for the plants.
An aquaponic grow system is the most productive form of agriculture per square foot. It can produce between three and six times the amount of vegetables than traditional farming while using approximately 1% of the fresh water. This makes it an excellent option for those with limited access to land and/or water. Aquaponic gardening not only produces a high yield of great-tasting produce, but because fish and pesticides are not compatible, it is also an organic system.
The drawback with aquaponics is the same as with hydroponics. It is economically challenging with its start-up and operational costs. A large-scale system is more economically feasible than a small one, but any vegetables you sell will have to be priced to support the system. This usually means higher prices than are readily available. Before you decide to jump into the aquaponic market, start small to refine your technique and test the market.
There are a lot of choices when it comes to stocking your tank and growing your vegetables. Some fish that have great results in an aquaponic system are tilapia, bluegill, sunfish, crappie, koi, fancy goldfish, and various ornamental fish. Plants that do well in any aquaponic system are leafy lettuces, kale, swiss chard, basil, mint, watercress, chives, and most common houseplants.
Once you progress to a larger system, you can grow more vegetables. Tomatoes, peppers, cucumbers, beans, peas, and squash have higher nutritional needs and will only do well in a heavily-stocked, well-established system.
Small Aquaponic Garden Supply List
These directions will build a small system. If you decide this is something you would like to explore, you can scale up to meet your needs.
- Three 20-gallon aquariums – This can be any plastic or glass container that holds water. You can support up to 2 square feet of growing area for every 10 gallons of water, so the larger the container, the bigger the grow-bed.
- Gravel – The bacteria necessary for converting ammonia to the nitrate needed by the plants makes its home in the gravel. You will need 2.5 pounds of gravel for every 5 gallons of water. You can use either natural or colored aquarium gravel but you must wash it before putting it in the tank or it will cloud the water.
- Small circulation or fountain pump and 3 feet of plastic tubing – The water pump is needed to pump water from the tank to the grow-bed. The water will then drain back into the tank. You need enough plastic tubing to go from the outlet on the pump to the top of the grow-bed and to loop a circle inside the bed.
- Aquarium air pump – The air pump blows air into the water for both the fish and the plants. Get the pump that is sized for the number of gallons of water in the aquarium.
- Air stone and 3 feet of air tubing – The air stone breaks the stream of bubbles, greatly increasing the oxygenation in the water. The tubing will connect the air pump to the air stone. Make sure the tubing fits the air pump outlet.
- Grow-bed – Any container that can sit on top of the tank and is 3-8” deep is fine. It should be slightly larger than the length and width of the tank. You can build a grow-bed out of plexi-glass and seal it with non-toxic glue. Building your own grow-bed allows you to accommodate an aquarium light by making a cavity in the bed that the light can slide into. If you are using a ready-made container, simply sit the light behind it.
- Growing medium – Use any chemically inert material such as pea gravel, perlite, coconut coir, or peat moss. This material holds the roots in place and helps maintain moisture. You need enough of this material to fill the grow-bed.
- Fish and plants
- pH test kit and a pH up or pH down product, depending upon the pH level of your water – The test and pH product can be found at any aquarium store.
- Drill with 3/16” and 1/2” bit
- electrical tape
- Aquarium heater – If you are using ornamental fish in your aquarium, you will likely need an aquarium heater as most ornamental fish originate in tropical waters. Choose from either a submerged or side-mounted heater that is the correct size for the number of gallons in your tank. If the system is placed in an area with a constant room temperature of 70-76 degrees Fahrenheit, or if you are using cool water fish, you do not need an aquarium heater.
- Tank light – If you want to add a fluorescent light to the tank in order to see the fish you may do so but it is not necessary to the functioning of the system.
- Plant grow light – If your system is set up in a low-light area, you could benefit from installing an artificial light system. Bright light shining directly onto the aquarium will encourage the rapid growth of algae. Arrange the system so as to provide more indirect lighting or buy one or two plecostomus, an algae-eating fish. If the grow bed is situated near a sunny window, in a greenhouse, or planted with shade-loving plants, you do not need a grow light.
Before you assemble your system, thoroughly wash and rinse the gravel.
Start the assembly by drilling holes with the 3/16” bit every two square inches in the bottom of the grow-bed. These holes allow the water that will be pumped into the grow-bed to drain back into the tank. Drill a hole in one of the back corners of the grow-bed with the 1/2” drill bit. This is for the water-pump tubing.
Set the water pump in the aquarium and the grow-bed on top of the aquarium. Feed the water pump tubing through the 1/2” hole, leaving enough tubing to coil around the inside of the grow-bed. Cut off any extra tubing and seal with electrical tape.
Add growing medium to the bed to just under the top of the tubing. Puncture small holes in the tubing that is coiled in the bed. Space the holes approximately two inches apart. Cover the tubing with another inch or two of growing medium.
Fill the aquarium with water. Plug the pump in to ensure that the water is continuously pumped from the tank into the grow-bed, trickles through the growing medium and back down into the tank.
Once your water pump is functioning, connect the air pump to the air stone with the tubing. Put the air stone in the bottom of the tank. This should cause a steady stream of bubbles.
Check the pH level of your water. Test kits are available at aquarium stores. If the pH level is higher than 7.2, use a pH down product. If it is lower than 6.8, raise it with a pH-up product. Let your system work without fish or plants for 24 hours in order to clear up any chlorine in the water.
After the system has sat for 24 hours, add the fish. It is recommended to start with 1/2” fish per gallon. Increase the fish density to 1” per gallon after a full month of plant growing.
In order to ensure the system is functioning at a high level, wait four weeks before adding plants. If you cannot wait that long, sprinkle some leafy lettuce seeds in the growing bed. The only true maintenance for this system is to feed your fish daily.
Whether you are interested in creating a hydro/aquaponic business, grow a salad on your kitchen counter, or interest your children in science, these are fun and satisfying systems to build and use.