July Aquaponic Update

Those people who follow me on Facebook, Twitter or Instagram know I started an aquaponic system earlier this year. An aquaponic system is a closed ecosystem where fish and plants are raised together. The system is self sustaining, and after it gets going it will accelerate as the fish grow, nitrogen fixing bacteria become better established, etc. If you are interested in learning more about these systems, The Aquaponic Source hosts a large discussion forum and provides many other resources.

I set my aquaponic system up in January, but it did not successfully "cycle" until mid-May due to some errors I made in maintaining the system chemistry. Cycling is the process of getting the nitrogen fixing bacteria established to convert fish urine to nitrites and nitrates. Without it, no fertilizer is created to support plant growth and ammonia builds up, eventually killing the fish.

The results of successfully cycling my system have been dramatic. After having about ten fish die as a result of excess ammonia, the remaining 25-30 tilapia are thriving, and have roughly quadrupled in size. The plants are mostly thriving, growing quickly and appearing healthy and vigorous.

The two biggest exceptions to my comment about the plants thriving are two culinary perennials I planted before the system cycled, kaffir lime and curry leaf plant. Both of these are used in Asian cooking, and the curry leaf is critical to South Indian cuisine. The kaffir lime is surviving, but not thriving (above). The leaves have yellow speckles and it has only put out a few new leaves (which seem to appear an entire branch at a time).

The curry leaf plant (not pictured) I think is almost dead. It puts out a few new leaves, but they have been curling up and falling off. Now that the system has cycled I am going to try starting with a fresh plant.

My tomatoes are a mixed story. The plants and foliage are growing vey well, and the few fruit are juicy and delicious. However, few new fruit are setting. My theory is I planted too many plants, and the system is too recently established to provide the nutrient density to support active fruit production. I am going to try pulling out most or all of the current plants, and seeing if a few plants of small tomato varieties can produce better. Photos below show the few fruit produced, and the dense tomato foliage with few fruit.

Herbs have been my biggest success so far. We now use basil from the aquaponic system, including Italian, red and Thai for cooking and garnish. It is absolutely thriving. Our thyme is more vibrant than any thyme I have grown outside, and we also have Mexican oregano and tarragon that are doing well. The only exceptions on the herb front are cilantro and parsley. They have just not done well. I am not sure the problem, and I am going to try these again starting myself from seed rather than buying plants.

I also have two other plants that so far are doing well. I have a recently planted jalapeno that has started to flower and put our new leaves. I will be interested to see if it suffers the same problem as the tomatoes, all leaves and no fruit. I also planted lemon grass, and it loves its new environment. I have a suspicion that within a few months it may take over more space than I want to give it. Fortunately it is a versatile plant and I am sure I can find ways to use however much I can produce. If nothing else it makes great gin & tonics.

June Aquaponic Update

It has been over ten weeks since ANY blog update, and more than that since an update on my aquaponic system. I have made a lot of progress.

After several frustrating months trying to get the system to cycle (establish nitrifying bacteria to convert fish waste into nitrites and nitrates) I sought help from the internet (specifically The Aquaponic Gardening Community). I was to the point where fish waste was building up, raising ammonia levels in the water causing the fish to start dying. And my plants were not growing at all.

Fortunately the main fix was easy. My water pH was too low, the nitrifying bacteria could not live, and hence no cycling. When I fixed the pH, it was pretty amazing how fast the cycling progressed, really over a period of only 3 - 4 weeks. Once the system began to produce nitrates, the plant growth exploded.

The above photo shows a small kaffir lime plant. The leaves in the background were on the plant when I put it in the grow bed. Before the system chemistry was corrected, they were turning white and falling off. I thought the plant was going to die. The healthy left foreground leaves have all appeared in the last six weeks.

Lettuce was one of the first things I planted in the system, probably in February. The plants did nothing, barely staying alive, until the system cycled. Now they are thriving. It is really too warm for lettuce and it is a little bitter, but it is great to see it growing so fast and know that in the fall and winter I will be able to produce great salad greens.

I have planted Thai and Italian basil, and both are growing quickly. These are the first plants I am really harvesting and using. The basil is delicious, and it is so great to be able to cut it, chop it, and have caprese salad with fresh basil and none of the waste that comes from buying bunches of basil at the farm market or grocery store.

My tomato foliage is thiving, and the plants are starting to set fruit, though I have had far more flowers so far than I have baby tomatoes. I understand that it takes a while to create enough nutrients in an aquaponic system to support fruit growth (as opposed to just foliage like basil or lettuce). I also think I was overly ambitious with the number of tomato plants I planted. I need to thin them out in the hopes that those remaining will have enough nutrients to set and produce fruit, but it is a hard decision to pull out plants (even though I would try to move them to outdoor containers).

This post has focused on the plants, but my tilapia are also much healthier since I sorted out the system chemistry. They are growing, and I think have doubled in size (at least) since I introduced them to the system a couple of months ago. I did have about a dozen die before I got the system working correctly, but I still have 25-30.

I have a few further corrections to make, and I continue to experiment with plants. I ordered chelated iron which I am hoping will help a few plants that are turning yellow or still not thriving (parsley, cilantro, curry leaf). I added two lemon grass plants today, and I think they will do well. Actually hoping they don't do too well - I have a suspicion I will be dividing them frequently. I have other herbs that are well established, including some tarragon and Mexican oregano. Overall while the system has a ways to go, I am at least seeing its potential, and the fantastic pace at which plants grow in an aquaponic system.

Aquaponic System Update - Slow Progress & Questions

I am learning a lot about our Aquaponic system, perhaps most of all that it needs to be warmer to operate successfully. I have also learned that sometimes a little bit of chemical can have a big impact. At this point I think I will wait until the system warms up naturally and finishes cycling before adding fish, but for next winter I need to find either a way to heat the greenhouse directly, or a more powerful solution for heating the fish tank water.

For any Aquaponics veterans reading this, I have some questions at the end of the post and would welcome feedback in the comments section.

At this point all of the infrastructure is set up and operating correctly. The 200W LED lights are hung, timers are operating and all the water is flowing correctly.

The 180 gallon tank is full, but bowing. This is not getting worse, so I am not too worried about it. I am considering how to insulate the fish tank, and this may lead to also bracing the side. I have been very surprised at how fast the water temperature in the fish tank adjusts in reaction to the ambient air temperature. The three heaters on the lower right can't seem to keep the water more than 10 degrees fahrenheit above the air temperature.

I have also been surprised (and frustrated) getting the pH right. Our tap water is about pH 7.8. I added what I thought was a little pH DOWN to try to get it closer to 7.0. I way overshot, and suspect I took the pH down under 4.0. It has taken more than a full bottle of pH UP to restore proper pH. I was surprised that the pH UP and pH DOWN chemicals had very different impact for the same amount of added chemical. (Both chemicals are from the same company, Pondcare.)

Because of the low water temperature, the cycling is going very slowly. Nitrites are currently up to .5 ppm, but the nitrification process only seems to work when the water temperature gets above the low 60s. In Virginia, I am expecting to see the greenhouse warm enough to consistently support this water temperature by mid/late February.

We had a spell of warm (65+ degrees fahrenheit) weather earlier this week and the water was up to 68 degrees. I have found that when the sun is bright, even though it only shines on the greenhouse for about 2-3 hrs, it has a big impact on the temperature. The high temp in the greenhouse in January was 91. However, when the air cools off, the water cools off quickly. It when from 68 to under 60 in 24 hours.

In addition to temperature and chemical challenges, I think the lights may be too close to the plants. I planted two small perennials from Logee's Greenhouses about three weeks ago when I installed the lights. The one on the left is Curry Plant, and the one on the right is Kaffir Lime. So far they have not died, which considering the cool greenhouse and lack of nourishment is not bad. However, the leaves closest to the lights are starting to discolor, especially on the Curry Plant. Right now the lights are hung about 18" above the surface of the grow medium. I am going to try raising them 6" and see if that helps.

Based on the current status of the Aquaponic system, I am working through the following questions and welcome input.

1) Should I brace the fish tank so it does not bow so much on the right side?

2) Should I insulate the fish tank, and/or make an insulated cover?

3) My original thinking was to heat the water in the fish tank, and let the water warm the air in the greenhouse. I am revising my thinking and for next winter leaning more to a combination of heating the greenhouse itself, and insulating/heating the fish tank. Does this make sense?

4) What are the minimum winter water and air temperatures to keep the fish and plants healthy and growing?

5) How far above the plants should the LED lights be hung?

Building our Aquaponic System - Part 2

Over the last month, I have put a lot of time into our aquaponic system. In brief, I had to install all the PVC plumbing, get the water flowing properly, add the grow media, install heaters, and begin hanging the lighting. The majority of the work has been associated with plumbing. There are still a few small leaks, but it all functions properly. There is still a lot of work to do, but having the water all flowing correctly makes me confident I will soon have a variety of plants growing, and a crop of tilapia.

I have tightened the grow bed stands, aligned the grow beds, filled them with grow media and started the water flowing. The syphons all worked on the first try, and I have adjusted the flow so the beds fill-up in roughly the same amount of time. I have the rigs partially built to hang the lights, and will finish installing them this weekend.

Yesterday when I first filled the system the water temperature was 46.9F. This morning it was 52.3F. I have 3 400W heaters running, and hopefully by this weekend the water will be up to 70F and I can start the cycling process. I think by that point the greenhouse will be a steam bath, but I am sure that will be good for the plants.

Many thanks (again) to Sylvia and her team at The Aquaponic Source. The binder of instructions for building the system has been very good. There are a few topics that I would modify but overall I have been able to make everything work as described.

This is a 180 gallon tank, which takes up more room than I think I expected. Soon it will be home to about 40 tilapia. First, the three heaters in the lower right need to do their job and get the water temperature up to about 70 degrees (fahrenheit). When I added water to the tank, it was about 45 degrees, and it is now up to 53 degrees. I suspect it is taking a lot of electricity to get the water temperature up to where it needs to be.

The plumbing has been the most time consuming part of getting the system set up. It started out easy, but as more and more pipe components were attached together, it became challenging to get everything to fit properly. I made several modifications to the original instructions, including liberal use of zip ties. It became a lot easier after I was clear in my mind how the water was intended to flow. All the pipe connections that are supposed to be glued have been, but a few of the others need to be tightened further with a pipe wrench (that I don't have yet).

The next step in the process of establishing the aquaponic system is 'cycling' which means establishing the bacteria necessary to the nitrogen cycle. I can start adding leafy plants like lettuce while cycling is in process, then when it is complete in a few weeks I will add tilapia. The bigs tasks for the remainder of Christmas vacation will be starting cycling, installing the grow lights and starting some lettuce seedlings.

July Aquaponic Update

June Aquaponic Update

Aquaponic System Update - Slow Progress & Questions

Building our Aquaponic System - Part 2

My Old Shoebox