This is probably the shortest Article I have written to date. But, I promised an update at the four week mark so here it is. Overall, Using Hydroponics to filter Koi Pond water and grow vegetables has been an overwhelming success! I’ve learned that there are some plants that seem to thrive in this environment as well as some that simply don’t like it. I’m sure the water chemistry is the reason plants either thrive or don’t. Considering that the entire reason for this is to help filer the Koi Pond water, I wont be tampering with the water chemistry for the sake of the plants.
Results for the Koi Pond Filter Experiment
Plants that Thrived in the Hydroponics
By far, the one plant that absolutely loved this environment are the tomatoes. The tomato plants I put in here are doing absolutely fantastic. They are three times the size of the ones I planted in the garden. The growth rate on the tomatoes is phenomenal and I had to introduce stakes to hold them up shortly after a week. I will probably have to keep them trimmed so they don’t overrun the entire hydroponics system. The root system on the tomato plants is extensive and runs well into the hydroponics tube.
The next plant that thrived in the filter was sweet basil. These plants skyrocketed and for the type of plants that they are, grew to a fairly large size with a nice healthy production of basil leaves . The Greek Oregano and the German Thyme are all doing good as well. They font have the crazy vigorous growth that the tomato and basil plants had but are doing well nonetheless.
Plants that Did Not like the Hydroponics
Cilantro, the Cilantro basically withered away and looked pathetic after just two weeks. I ended up pulling them out and replanting them with two pots of decorative grass. My idea is that towards the end of the season, assuming they do well, I’ll transplant them to around the pond itself.
Green beans. I’m still on the edge on the green beans. I planted the beans in the coconut coir and stuck them right in the hydroponics tube. The two that germinated look spindly and unhealthy. I suspect that had I germinated them outside of the hydroponics environment and then transplanted them after some growth they may have done better.
The Koi Pond Itself
Not a lot to say here other than that the water is crystal clear. I don’t have a nitrogen test kit to do before and after but can see that the water is clear and the Koi are thriving. In any event, don’t think that testing for nitrates would have revealed much. There are a lot of other factors involved including the natural nitrogen cycle in the pond itself as well as the water plants in the pond. The pond is well established (over 8 years) so should have most if not all of the elements needed for a healthy ecosystem. The hydroponics filter is an added plus to help pull the nitrates from the pond.
- Don’t place plants with large root structures near the exit tubes of the hydroponic tubes. This in and of itself, did not cause a problem for me. I did notice that the roots will grow in the direction of the water flow, however gentle it might be. Placing these plants near the exit flow could result in clogging them and losing significant amounts of water.
- Do daily check of your system. There were a few days where some of the hose connections developed leaks. These were small and inconsequential and could have been avoided by using hose clamps. But I still think that a daily check is wise to avoid catastrophes in your hydroponics Koi pond filter.
- Avoid Plants that don’t like the water chemistry or environment. One plant that did not do well at all on my list is cilantro. They just gradually withered away.