Aquaponic Gardening…….another hobby
October 2, 2014
From the desk of Dr. Voorheis
At the beginning of this year, I said that most of he blog would be about veterinary medicine and every once in a while I would write something a bit more personal for good measure. This week, it’s personal. I’d like to take you all on a gardening and science adventure and tell you all about one of my favorite hobbies….Aquaponic gardening!
I have always been a gardener. Going back to being a kid in a rural setting, there were always spring and summer gardens. I’ve carried that through my adult life as well. There is nothing quite like home grown vegetables. They actually have flavor because they ripen naturally as opposed to being ripened by exposure to ethylene gas. They still have vibrant flavor as opposed to those selected for toughness of skin and even ripening so they can be picked by automated machines. As much as I don’t want to sound like someone yearning for the “good ole days”, vegetables used to taste better than they do now, especially tomatoes. Yet I have also had my share of frustration with my traditional gardens. Tilling the soil and pulling weeds is not exactly how I want to spend my precious time off. Although I will admit to some satisfaction from digging in the dirt, it is not nearly as much fun as I might romanticize it to be. In all honesty, I can gear up to working in the soil only a few times a year. It’s not much fun to have to maintain my backyard garden week in and week out. Really, the time just isn’t there.
I also like to tinker on things, build things. So when I found out a little bit about aquaponics, I thought it sounded pretty darn cool. “Doc – Aqua what?” Aquaponics is a food production system that combines conventional aquaculture (raising aquatic animals such as fish, crayfish, or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment. With aquaculture (think most of the fish that we eat or buy in the grocery store), fish are raised in large tanks in a closed system. The waste products of these fish in an intense grow system require that at least 10% of the water needs to be removed and exchanged every day. If the waste products from the fish are not addressed on a daily basis, waste products accumulate and the water becomes toxic and the fish die. A tremendous amount of monitoring has to happen in these tanks where fish are raised for food. Aquaculture is a very water intensive process. It doesn’t sound attractive to an environment that is in the middle of a drought.
Hydroponics is the raising of plants in media (soil free, i.e. rocks or hydroton) being fed a nutrient solution (water + needed nutrients) tailored to the requirements of the plant species.
As with aquaculture, hydroponic operations need to carefully monitor the water environment to ensure the highest yield.
In an aquaponic system, water from an aquaculture system is fed to a hydroponic system where the by-products are broken down by nitrogen-fixing bacteria into nitrates and nitrites. The nitrates are utilized by plants as nutrients. The nitrites are further broken into nitrates by other bacteria. The water is then drained and re circulated back to the fish, oxygenated and void of its toxic nitrogenous waste. There is no need to remove water from the system.
In brief, by combining the two systems, they complement one another perfectly. Fish produce the nutrients that the plants need, bacteria in the grow beds remove the nutrients that kill the fish, and oxygen levels are maintained by the cycling of the water through a natural system similar to that found in nature.
A few years ago, I decided to try this aquaponic thing. Mostly I didn’t know what I was doing, but I read and researched as much as I could on the subject. I found out I would need a few grow beds, a large tank of water for the fish (275 gallons), and a sump tank (also 275 gallons). For a backyard gardener raising fish, I learned tilapia were probably the most resilient fish when it comes to temperature fluctuations and other screw ups by the farmer. Believe me when I say I screwed things up more than once and tilapia are a very resilient fish.
I built 3 grow beds (3’ x 6’ x 1’). I then lined them with pond liner. I put a large pump in a “sump” tank (a large IBC tote cut to hold 275 gallons of water. I used another IBC tote as a fish tank. Water is pumped continuously to the fish tank and to the grow beds. When the grow bed fills, the water is returned to the sump tank by means of a “Bell Siphon” pictured above.
My pumps (there are two) because of distances of grow beds to sump tank, are powered by solar energy (in fact my whole house is but that is another subject).
The sump tank as it initially filled.
This picture is one of the grow beds a month into the first growth cycle. The grow media is “expanded shale”. It takes about a month, of plants only, for the water to complete the nitrogen cycle. Cycling is really shorthand for the establishment of a biofilter where the nitrogen cycle can take place within your system. The nitrogen cycle is the ongoing process in which bacteria convert ammonia and nitrites into food that your plants can consume. That food is nitrates.
This is another grow bed about a month into the first cycle with strawberries and cilantro. I have grown the following vegetables and herbs with significant success:
- Tomatoes – all types
- Swiss chard
- Onions – yellow and white
- Peppers – all types
- Romaine lettuce
- leaf lettuce
- spinachMy current winter crop is an entire grow bed devoted to lettuce. I also have basil, peppers, and cauliflower started for fall. Tomatoes are still producing too. I’ve got a number of different herbs growing as well. Less success with squash and cucumbers… I still grow those in dirt.
One of the end products was these fish. They were harvested at a BBQ at my house over Labor Day weekend. It was fun because anyone who wanted fish literally had to catch their own fish! These tilapia were about 14 to 15 inches in length and weighed over a pound each.
I enjoy my aquaponic garden a great deal. I undertook the project because it was challenging, fun, and I wanted to learn more about a different way to garden. It has also given me a lot to think about. I will now jump into some uncharted waters. Whether or not you think “Global Warming” is real, or that our climate is changing, it is undeniable that we are suffering a significant drought here in the West. It seems rather evident to me that it makes sense to pursue gardening and farming practices that conserve water, and certainly aquaponics uses a fraction of the water of traditional agriculture practices without using any fertilizers or pesticides. This is sustainable gardening at its best. In some countries of the world, for example Australia, aquaponics has huge support on the government level and on the individual level because of the opportunity to produce a significant amount of food using smaller space and less water. I believe that eventually aquaponic gardening will take off in popularity, simply because it makes sense and it works.
Next blog in two weeks will be on pancreatitis. Until then………