Aquaponics experiment 2013: harvesting the vegetables!

It’s been a while since the last update, so much so that all of the vegetables have been ready to harvest for the last couple weeks! Once the system had been built and the bacteria cultures established, all I really had to do was sit back and feed the fish, and maintain the siphons and pump every once in a while. There are still a few weeks left before I will officially say the season is over, but I can safely say that this experiment was a great success!

General maintenance routine

Throughout the summer there have been a couple of things that I have had to do over and over as regular maintenance for the system, but nothing that was ever too taxing. I checked the system nearly every day to stay on top of potential issues, but the last two months have been very smooth sailing. Here’s what I had to do every few weeks:

Cleaning and maintaining the siphons
I knew that I’d have problems with algae when I chose to use clear tubing for my siphons, but it really hasn’t been very difficult to maintain. When algae grows too much in the siphons, I simply remove them, bend them in a few places to break up the algae then run tap water through the tubing. If that doesn’t clear the algae, I shoot compressed air at ~40PSI through it, which always does the trick.

Every now and again I’d have to reseat the siphons, or bend them back into shape. I suspect that the summer heat has a tendency to distort the tubing over time. I eventually ended up using loops of twine to hold the top of the siphons up and help it maintain a good shape.

Sometimes the siphons would get pinched where the loop was tightest. To fix that I would remove the siphons, clean them, then place them in a vice and squeeze hard from the sides. For good measure I also used a handheld torch to soften the plastic before squeezing, then quenched the tubing in cold water afterwards.

The pump and bed inlet system
As I expected, the pump needed to be cleaned about once every two weeks or so as debris clogged up the filter. This is a very easy fix as the pump is designed to be cleaned very easily. The filter and plastic cover pop off easily, which I was thoroughly in the sink to remove any debris.

Surprisingly, the pump is still going strong and only really had one serious problem earlier on. Awesomely, a friend fixed it before I got to it (thanks Chad!) by cleaning the impeller assembly inside the pump.

Water level top offs
A certain amount of water is naturally absorbed by the plants and more water is naturally lost due to evaporation in the summer heat. Depending on the heat, I usually have to add about 25-50 gallons of de-chlorinated water to the fish tank about once every week or two. The temperatures dropped to the mid-80s for a week or so recently, and I noticed that I didn’t have to add any water for a while. This past week, however, has been back up in the mid to upper 90s, so I’ve had to add water every 3-5 days!

I fill a separate 50 gallon barrel with tap water, then wait at least 24 hours for the chlorine to evaporate before transferring it to the fish tank.

Tomatoes

Along with the broccoli, the tomatoes apparently love being in an aquaponics system! In fact, after the lettuce it was the first plant to produce edible food! And unlike the melon and eggplants, the tomatoes tasted great! I’ve been harvesting 3-5 tomatoes every day for the last two or three weeks or so, and it looks like that number is about to go up very soon. Right now there are TONS of green tomatoes growing on the plant (possibly a few dozen) and should be turning red pretty soon. It may be time to try to make some salsa or something!

Eggplant

The eggplant did quite well and didn’t really have any growth or fungus problems throughout the entire experiment. It produced a handful of fruit, but unfortunately they were a tad too bitter for me. I’m not sure if this means that they are not well suited for aquaponics, or if I neglected to do something for them.

The variety that I planted yield smaller eggplants than you’d buy at a supermarket – about 6″ in length. I will probably try another variety next time to see if they come out any less bitter.

Jalapenos

I wasn’t sure if the jalapenos would be good or not because I’ve never eaten a jalapeno raw and didn’t know what to expect. Today I tried one and it was very spicy – like…a jalapeno. I think I will take a few and try to pickle them, then take another and make some guacamole (maybe with some of the grape tomatoes!).

The plant is yielding about a dozen jalapenos right now, ready to pick, with a few more white flowers developing. Hopefully I will get a few more before the season is over!

Lettuce

The first plant to be harvestable was the buttercrunch lettuce on the far left side of the left bed. The leaves were edible almost immediately, and were not bad for a while. Unfortunately, I was too amused by the astounding growth rate of the plants to do learn more about it, and let them them all flower. As soon as it flowered, all of the leaves began tasting very bitter and were pretty much inedible because of it. Next time I plant lettuce, I now know to cut off the tops before the flowering starts!

After the leaves turned too bitter to eat, I decided to pull the plants out completely, because their roots were just sucking up nutrients that the broccoli could use instead. This gave me a chance to examine the root structure of these plants, which was surprisingly dense! You could actually pat the gravel and it felt very solid!

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Broccoli

The broccoli seemed to do the best throughout this entire experiment. I never had any growth problems or bad fruit or anything. Their roots are extremely dense and strong, and their stalks are very thick and solid. Occasionally a leaf would turn yellow, which seemed to always be with leaves that were not getting enough sunlight.

Last week I started harvesting them, simply by cutting the stalk just under the head. I used some in a pasta dish, and it tasted just fine! Success!

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Zucchini

Unlike the broccoli, the zucchini that I planted never really did well. Early on they developed such long and dense roots that the siphon for the right bed became clogged from the inside, so I actually had to rip up the plant nearest to the siphon and dig down through the gravel to clear the blockage. I don’t think the plants ever recovered from that.

After a while, small white patches of fuzz (possibly a fungus?) started to grow on the leaves of the zucchini, eventually spreading to cover the leaves and killing them. Almost every day, the plants were producing yellow flowers that would bloom, then close back up and fall off. One plant actually produce a very weak fruit about 3 inches long, but it was a lost cause. I decided to rip up the plants to prevent further siphon problems and get more nutrients to the other plants.

I actually removed the zucchini a while ago, and wrote about it in my previous post.

Mystery melon

I planted some sort of melon / squash and promptly lost the label to it, so I just let it grow to see what would happen. It was doing very well for most of the summer, growing out into a very long vine. A since fruit appeared one day and began to grow dramatically every day.

Unfortunately, those stupid little blue fuzz balls showed up on some of the leaves and eventually took over the plant within a couple weeks. The leaves all withered and died, and the stem shriveled up. The melon itself looked a little misshapen and quickly lost it’s color, so earlier this week I thought it was about time to just yank it out.

I cut open the melon just to see what it was and was surprised when a good amount of water fell out! The inside of the fruit looked very full of water and very much alive! Although it smelled great (like a cantaloupe), the flesh was pretty tasteless.

Oh, and someone tells me that this is probably a muskmelon, which I agree with. The outside doesn’t look very good, but the inside is spot on.

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Next up

I will be harvesting veggies for the next few weeks and keeping an eye on the weather forecast. When the temperature starts dropping I will try to catch and, uh, harvest the biggest catfish in the tank. I will probably invest in a smallish aquarium heater to keep the water temperature up and see if I can’t grow the catfish out during the winter. On goes the experiment!