Successful Bioponics system test: Growing Lettuce with Vermicompost Leachate

On February 27th of 2018 we completed a successful test growing lettuce using only vermicompost leachate in a hydroponics system.

The system was a continuous flow media bed system with the seeds being seeded directly in the media bed of this old aquaponics system. As you can see by some of the pictures the growth was great even though there were a few minor issues in the leaf tissue occasionally.

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The system was also designed to return the water to the bottom aquarium (the sump) with the biggest splash possible, which oxygenates the water but on the other hand is noisy. The system was being dosed with ~50-200mL of coffee-filtered vermicompost leachate every week, and I was also adding phosphoric acid (pH down) every week to keep the pH in the range 5,5 – 6,5, since the system had a tendency to increase the pH over time. So every week the inputs were: tap water, vermicompost leachate, and phosphoric acid.

The tests I did were mostly qualitative to try and see any apparent tissue damage on the plants. Some of us tasted the lettuce and the taste was good and comparable with regular hydroponics and aquaponics, however we have little knowledge of how potentally harmful compounds added to food (such as pesticides) are transformed during vermicomposting, and how they interact with the plants growing from the vermicompost leachate. It is possible that long-term hazardous health effects from regularly consuming plants grown in this way exist, so be aware of that if you are planning your own experiments.

Prototyping a Solar Thermal Collector using Aluminium Cans

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The following prototype is the first attempt at building a Solar Thermal Collector using a waste product such as aluminium cans. The concept is simple: the sun’s radiation heats up drilled cans painted black, heating the air inside, while a fan moves the hot air to the intended destination. The cans are drilled in the bottom and the top, and stacked on top of each other. As the hot air naturally rises, it is removed by the fan so that the cooler air enters the panel through openings at the bottom.

Despite this being a very crude first attempt (the acrylic glass is barely transparent, it is not the target thickness, it has cracks and it is not sealed in the edges), we were able to output air with a temperature of 38ºC in a spring day with less than 20ºC of ambient temperature earlier this year.  We are now working on optimizing the design for two goals:

  • Find easier materials to source and work with, and write the instructions for this design;
  • Experiment combining this thermal collector with a heat engine, so that during the summer the heat of the sun can be used for mechanical work or for electricity generation.

 

Experimenting with Portable & Passive Hydroponics

I have been experimenting with portable and passive solutions for hydroponic systems. The objective was to have a system as simple and maintenance free as possible. Two types of packages were tested: Tetra-Pak or similar and PET bottles. The Tetra-Pak or similar were ideal since they protected the nutrient solution from light. While growth was fast, some fungal activity was detected in lettuce leaves, and some of the packages started leaking from the bottom after some weeks of use.

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The PET bottles are behaving surprisingly well. I was unsure if their transparency would affect plant growth since it’s usually believed that roots should be protected from light. But the plants have been experiencing some growth, despite light exposure. As expected, algae growth can be observed in the walls of the PET exposed to the nutrient rich solution. Whether they will affect the growth of the target plant or not remains to be seen.

Some of the challenges that need to be addressed before creating an instruction for this technology include: finding the best material for container (preventing leaks and light), and incorporating these vertically without danger of spillage.

OikoSol’s Vermicomposter in action

Here you can see a picture of OikoSol’s vermicomposter in action. It has been working without problem, managing to consume around 1 Kg of organic waste per 2 weeks (approximate figure), as well as ~200mL of vermicompost tea per week. It was observed that other organisms have populated the vermicomposter, including mostly thrips and compost mites. But these have been contained to the compost as it is always closed. There have been no issues with smell, which is a good result considering this one is positioned inside a kitchen.

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Updated Logo

A new logo has been made to better reflect the ideas and goals behind OikoSol in a more appealing and elegant way. The logo was made by deviantart user “vexilologia” as part of an ongoing series to create a new logo/flag to represent OikoSol

oikosol_logo_2016

Second instructions released: Vermicomposter v.1.0

The second Soleco instructions have just been released on the OikoSol website:

Vermicomposter v.1.0

For those of you interested in tweaking it or just taking a look at the materials used, here is the page where newer and older versions will be added, as well as the materials to help you edit new versions (images, word file, and 3D sktechup file). If you want to edit it, share it first on reddit for everyone to see, vote and comment on.

 

First instructions released! Media Bed Aquaponics v.1.0

The first Soleco instructions have just been released on the OikoSol website:

Media Bed Aquaponics v.1.0

For those of you interested in tweaking it or just taking a look at the materials used, here is the page where newer and older versions will be added, as well as the materials to help you edit new versions (images, word file, and 3D sktechup file). If you want to edit it, share it first on reddit for everyone to see, vote and comment on.

The show has just begun!