Evaluating changes needed to our aquaponics system

We love the success of many of the things we were able to grow once we created our year-round, insulated greenhouse extension.  However, we did run across some problems.  We were also worried about the efficiency and sustainability of the system.

1) First of all, we were buying food to feed our fish.  Ultimately, we wanted to be growing food for the fish ourselves.  Having to buy food didn't seem very sustainable.

2) Our fish were mostly Tilapia, which are tropical fish and need warm water temperatures.  They were given to us by a friend for free, which is one of the reasons why we continued to use them.  Tilapia are also fine to grow in high densities, which makes them desirable for many larger aquaponics systems.  We realized eventually, however, that we do not need as many fish as we were growing, so switching to a lower-density fish would still be fine for our system.  We were also spending a lot of money heating the water, especially during the winter time when temperatures drop below freezing and commonly in the negatives.  We have just harvested about half of our Tilapia with the ultimate plan of switching to another breed altogether.

3) aphids, aphids, aphids.  The benefit of subjecting your garden to the whims of natural seasons is that many garden pests cannot survive the colder temperatures of winter.  When you have a nice warm year-round environment for these pests to grow in, numbers can grow out of control.  When the aphids first became a problem, their numbers were already substantial.   Aphids especially loved hiding in the new, curly growths on our kale plants.  It seems like I spent forever rinsing all the little crevices of kale that I harvested before I could use it to cook with.  Often, we just pulled the most infested leaves out and fed them to our chickens (The chickens love the kale and the aphids equally).  We tried everything we could think of to control our aphids naturally.  We pulled them off the plants by hand.  We used water to spray them off the plants.  We bought lady bugs for the greenhouse (twice now), but the lady bugs didn't seem to want to stay around.  I even spent a considerable amount of money on purchasing a parasatoid species of wasp that lays its eggs inside of aphids, thereby helping to control numbers of aphids in a population.  We never noticed if the wasps had an effect on the aphid population.  However, I knew I was taking a chance with these, since it was recommended that the wasps be used to control populations that were still pretty small and manageable.  Ours was already out of control.  We even created our own spray of garlic and pepper, which we sprayed on the plants heavily infested with aphids.  This seemed to help, but the aphids came back in full force after the spray wore off.  An important consideration when spraying anything on plants in an aquaponic system is the potential effects on the fish, because the spray can make its way into the water supply.  This is why we didn't want to risk spraying a natural pesticide, such as neem oil on our plants.  Neem oil eventually degrades and has no known negative effects when eating vegetables that have been treated with it, but we didn't want to risk the potential immediate effects on the fish.

Because of these concerns, and our desire to consolidate the indoor space to use for other needs (such as housing our rabbits), we began a new round of revisions and modifications to the greenhouse space.  This what Brian is working on now.  We harvested 31 fish and consolidated the rest to one tank.  Brian is also working on ways to control evaporation and heat loss from our system.  We are also going to harvest the remaining plants, clean the system thoroughly, and start over again with new seedlings.  We are contemplating the best way to rid our system of aphids before planting anything new.  The best idea so far is to clean out all the beds with hot water.  Hopefully, this will kill the aphids in all potential life stages.  If some return, we may be able to control the numbers with predators (such as ladybugs or parasatoid wasps) as long as we introduce them early enough to keep the populations down before they grow out of control.

Adding on and Revisions (number 1) to the Aquaponics System

Once we realized that direct sun from above was the key to growing our plants year-round, we had to revise the system.  Our choices were to to either convert the upstair level of the barn to a fully insulated and winter-proof greenhouse or to add-on to the lower level of the barn.  After consulting an engineer, we realized the cheaper option would be to create a greenhouse add-on that sloped up from the lower level to combine with the upper level.  Brian had been spending time collecting used and recycled windows and doors from free sources, online trades and deals, and shopping at places like ReSource (an organization that recycles old and use construction and home materials).  Because of this, we already had a large supply of cheap insulated glass.  We bit the bullet and paid good money for good insulated polycarbonate roofing material.  This polycarbonate material is worth the money.  It is 5 layers thick, with 4 layers of air insulation between the layers.   It is also strong enough to withstand the snow and winds we get on our property... both in substantial amounts.  We also purchased wood and some other new materials (screws, etc.) for the structure.  However, our goal was to use as many recycled materials as we could.  We obtained old tires from several different local sources and lots of cans and bottles from friends.  We used these to construct the foundation of our greenhouse extension.

We had to dig into the hill next to our barn to create the new greenhouse extension.  You can see the tires used as the base of the foundation here.  We packed them thoroughly with soil (leftover from all the digging) to create a solid base.  We modeled this building structure off of methods used in building earth ships.

Brian is working on the frame of the extension here.  You can see it coming from the tire foundation..

We used recycled windows for the walls and insulated polycarbonate material for the roof.  The nice thing about this extension is the height of the structure.  It is tall enough at the highest point to combine the lower and upper levels of our barn.  We still had non-insulated polycarbonate roofing on part of the upper level of the barn as well.

Filling-in the space between tires with old cans and bottles.  We later added a layer of cement to the outside of these materials.  The soil packed inside of the tires and the air inside of the cans and bottles provide extra insulation.

Adding more bottles and cans.

Our new extension gave us more space, more sunlight, and an insulated space for year-round growing.  The following pictures were taken when we first started growing in this new greenhouse extension.  Our kale, collards, chard, peppers, and tomatoes did well.  We also had some success with lettuce, broccoli, cauliflower, and a few other experiments.

And here is a link to a video of the system.  Sometimes, it is hard to see how things are connected from pictures alone.

video link

Creating a Sustainable System - Aquaponics and more - (The beginning)

Since our ultimate goal is to produce most of our own food, we have been interested in sustainable systems.  An aquaponics system seemed like a good place to start, since the idea of it involves creating a sustainable ecosystem that recycles its own waste, water, and nutrients in various ways.  If you've never heard of Aquaponics before, it is a combination of hydroponics (growing plants in a water instead of soil) and aquaculture (raising fish for food).  The concept is simple.  The fish release their waste products, which become nutrients for the plants.  By absorbing nutrients from the waste water of the fish, the water is filtered and can be recycled back into the fish tanks.

My partner, Brian, has a eerie ability to construct, modify and/or repair just about anything you can think of.  He can fix cars, build houses, and even help to heal your injured shoulder massage therapy.  With the exception of computers, he can create and repair just about anything.  Aquaponics, therefore, was something he immediately and somewhat intuitively understood the workings behind.  The biologist in me loves the idea of this system since a large part of it depends on understanding the intricate relationships between organisms and their non-living environments within an ecosystem.  My mind still struggles, however, with the mechanics of the system.  This includes creating a system that can distribute water to various growing beds in a way that allows the water level to regularly rise and fall within the beds.  The water then needs to be pumped back to the fish from the various storage tanks and recycled.  The water chemistry is fairly straightforward, but needs to be monitored regularly to be sure that the nutrient levels do not rise or fall too much.  The water also needs to be heated, since we live in the mountains at over 8000 ft of elevation.  Brian has built our current system by hand, using as many recycled materials as possible.  We have added and changed the system in increments.  Three years ago, we began converting the barn on our property to a space that was usable for aquaponics.  Here are a few photos of the process:

Our original plan was to put plants upstairs and fish downstairs, so we began with adding some polycarbonate material as roofing to part of the upper level of the barn.

Our first fish were goldfish.  We later added Talapia that were donated from a friend who is growing them.

We eventually took down the south wall of the barn and replaced it with free sliding glass doors we found on craiglist to create the large windows you see here.  This allowed us to have a heated and insulated space to grow the vegatables in the downstairs part of the barn.  The blue containers were 50 gallon recycled barrels that had been used to store soy sauce.  We obtained them from a container recycling center, cut them in half, cleaned out the soy sauce, and constructed grow beds from them.  The medium inside of them are expanded clay pellets.  In the winter, when the sun hit the barn at an angle, these windows worked nicely, but when summer arrived and the sun shone from directly above the barn, these grow beds were no longer receiving much direct light at all.

Our first round of growing vegetables in the system.

These lettuce plants were sitting on top of a Styrofoam layer that floated over a bed of water.  You can see the root system, which is usually submerged in the water.  Other plants grew in the larger beds (seen above) as the water level rose and lowered periodically. 

Although we were able to grow some fish and some vegetables with this system, we soon realized that there were some flaws.  (1) We used non-insulated polycarbonate material on the upper level of the barn with the intention of turning that space into usable greenhouse space.  Since we live at a high elevation, winter starts early and lasts late.  Temperatures drop into the negatives regularly.  The top floor of the barn, therefore, became a good place to grow plants only for the spring, summer, and fall.  Because of our insulated windows downstairs, we could grow year -round, but only had limited space for growth next to the windows.  (2) Furthermore, the windows did not allow for direct sun during the summer time.  We needed access to more sunlight if we wanted to grow some plants year-round.