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 Imagine if you could produce your own fresh food in a small
space and do it in an environmentally friendly and inexpensive way. Using
aquaponics (a combination of aquaculture and hydroponics), you can!
The system is simple. Fish are kept in a tank with grow beds
elevated around them. Water from the fish is used to irrigate and fertilize the
plants. The root systems of the plants and the growing medium remove nitrates
from the water to use as food. The water is returned by gravity to the fish
tank, aerating the water as it falls into the tank. This is a closed system that
conserves water, is organic, and closely mimics a natural ecosystem.
There are many ways to practice aquaponics, from small home
aquarium tanks with a few salad greens growing in the inverted lid to
warehouse-sized commercial operations. My family and I built a small system from
all found and recycled materials. It is watered by hand (thirty minutes labor
per day) so it does not use electricity. It takes up about one-and-a-half square
meters of space.
The idea for this system came to me after some repairs had been
done on the highway near where we live in rural Thailand. The road crews had
left behind a broken piece of culvert and a small pile of pea gravel. So I
thought, “Reduce, Reuse, Recycle!” I knew that the culvert could be used as a
fish tank with a little cement work, so we carted it and the gravel home.
The first step was to create a base for the tank using chicken
wire and cement left over from a previous project. The tank was placed on the
base and sealed in place. Then the tank was then filled with water from our
well. If you use chlorinated city water, remember to wait a week or so before
putting fish in the system, in order to allow the chlorine time to dissipate.
Tilapia fry from one of our aquaculture tanks were placed in the
tank and began the process of fertilizing the water. The only input into this
aquaponic system is food for the fish. If you use an omnivorous fish like
tilapia, all of their food can be grown for them. Duckweed is an excellent
complete diet for tilapia.
Our “free” aquaponics system has been providing us with fresh
greens and fish for six months now and will keep doing so for the foreseeable
future.
For the planters, we collected used plastic containers from our
village school and clinic. The tops were cut off and the containers washed very
thoroughly three times. Then a hole was made in the side of each container’s
base using an awl. This is to allow water to drain back to the tank. On the
opposite side of the containers, near the top, a hole was punched to allow two
containers to be connected using string. Doing this increases the number of
containers that you will be able to fit on your shelf.
The plastic containers
were filled with a mix of coconut fiber and rice husk because those are
materials readily available for free where I live. If you use coconut product,
you need to use chips and fiber, not the powdered coir soil amendment. If you
are not sure of the source, it should be soaked and rinsed very well as it may
have a high salt content. Coco chips are excellent in a hand powered aquaponic
or hydroponic system, as they retain moisture very well while still having
adequate air spaces for the plant roots.
An old board (see photo above right) from our farm’s plant nursery was
given new life as the shelf for the containers. It is more common in aquaponics
to use large growing beds but we were going with what we had or could source for
Seeds were planted and gravel was placed on top to prevent the contents from
floating out of the container when flooded during watering. Seedlings grown
using hydroponic media could also be used instead of seeds.
The containers were placed on the board so that their drainage
holes allow water to fall back into the tank. The containers were flooded with
water from the tank using a watering can without its “showerhead”.
(See photos, right)
Aquaponics meets all of the criteria for sustainable agriculture. It is
environmentally sound, has minimum inputs, eliminates the solid waste disposal
required by intensive aquaculture, and is socially responsible and economically
viable.
Our “free” aquaponics system has been providing us with fresh
greens and fish for six months now and will keep doing so for the foreseeable
future.
Aquaponics meets all of the criteria for sustainable agriculture. It is
environmentally sound, has minimum inputs, eliminates the solid waste disposal
required by intensive aquaculture, and is socially responsible and economically
viable.
Aquaponics provides you with an environmentally friendly way to
raise fish and plants in a confined space. A hand powered system uses no
electricity and minimal water. All fertilizer is provided organically by the
fish. A system like this is also very helpful in teaching children how an
integrated ecosystem (Planet Earth!) functions.
I find watching the fish and tending the plants very relaxing. I
also love to eat the fresh produce and fillets that the system produces.
Aquaponics is a sustainable, eco-friendly food production system that is in use
from Antarctica to the Arctic circle and from the deserts of Arabia to the
jungles of Thailand. If you have been thinking of producing more of your own
food, aquaponics is one good way to go about it. This is truly the future of food production!
J. Steven (Steve) Bird is originally from Calgary but grew up
both in Canada and Germany as his father was in the military. He has over thirty
years international teaching experience. For the last twelve years he has been a
farmer in Buriram province in northeast Thailand where he lives with his wife,
son, and daughter. In addition to his farm duties, he also teaches English,
Sustainable Agriculture, and swimming.
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Materials Required
To build a small hand powered aquaponics system you need the following
items:
- A tank to hold the fish. Anything that holds water can be used as a fish
tank. Some ideas are large plastic tubs, pre-cast fiberglass
tanks and solid-sided children’s wading pools. If you make your system
portable (with the water removed), you could even use it indoors with
the addition of grow lights. Good for those of you in cold, snowy
locations!
- Container(s) for plants. Plants can be grown in a single large
container, several medium-sized ones, or many small ones. Use your
imagination and what is at hand.
- Some means to elevate the plants above the fish. We used an old board
for a shelf.
- A watering device, such as a watering can without its head.
Tips on Start Up and Maintenance
- Place your fish in the tank at least a week before you add plants to the
system to allow them time to fertilize the water. In a system this size,
we have found no need to cycle water through the growing media before
planting but many sources advise you to do this.
- Before watering your plants, swirl your hands gently through the water
in order to put fish waste into suspension before filling the watering
can. At some point you may find that you have an accumulation of waste.
Move the fish to a temporary container, using the water from the tank,
clean out the tank and return the fish and water.
- Flood your containers three times a day or more.
- Feed fish according to age and type.
- The water in the tank will need to be topped up because of evaporation.
The best way to do this is with a strong spray. This fills up the tank
and provides extra aeration for the fish.
Climate Considerations
Protective Structures
Here in Thailand, we need protection from torrential monsoon rains and
also from forty-plus degree C temperatures. In temperate climates, you
will need protection from frost and cold. In our system, there is a
framework of three-quarter-inch PVC piping over it. This was made from
bits of pipe and junctions left over from a greenhouse project. We use
the frame to hold plastic sheeting in the monsoon season and shade net
in the very hot season. In a temperate climate, such as most of the UK
and the southern US, a single layer of thick plastic sheeting might
suffice for plant protection. In colder climates, a small greenhouse
structure would be better.
Plants and Fish
The types of plants that will grow in a garden are largely dependant on
that garden’s location. Any plants that you are already growing
successfully should do well in an aquaponics system. Water loving plants
such as lettuce and other greens do very well in an aquaponic garden.
Fish can be very temperature sensitive, so find out
which types of fish do best in your climate. In almost all locations, a
nearby fish hatchery should be able to provide both information and fish
fry or fingerlings.
Brrrrrrrrrrrrrrrr Locations
If you live in a really cold location, consider making your system
portable so that you can take it inside during the winter. Use of a
plastic or fiberglass tank instead of concrete and the addition of grow
lights make aquaponics possible all year round regardless of your
location!
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