Kokedama Power

Hi everyone! In this instructable, I’m going to show you how to create a bioenergy kokedama—a moss ball with a plant that can generate electricity using natural processes. This project combines nature, bacteria, and a bit of technology to create a living fuel cell that’s both beautiful and functional.

It’s a fun and eco-friendly way to explore renewable energy and see how life can generate power.

These bioenergy cells—also known as microbial fuel cells (MFCs)—use the activity of certain microorganisms to produce electricity from organic matter. Most studies and applications of these cells focus on treating wastewater, since during this process, not only is electricity generated, but the water is also cleaned—offering a double benefit.

This microbial activity also exists in the roots of plants, and that’s exactly what I’ll try to recreate here. The basic principle is simple: microorganisms feed on organic matter, breaking it down and releasing electrons in the process. Normally, these electrons would be lost, but in a microbial fuel cell, we capture and direct them through a circuit, generating electricity.

👉 For more resources and detailed explanations, check out this link: https://sancardiy.com/experimentos/celda-combustible-microbiana/

To carry out this experiment, you will need:

Agar Agar (Vegan gelatin) – This will be used to create the membrane for our cell. We’ll shape it into a small cup using a mold.

Substrate (the soil for the Kokedama) – You can use different types of substrates, from universal soil to bonsai soil or even a mix with perlite. I used regular garden soil (universal substrate) and added organic matter like sticks and dry leaves to provide food for the bacteria. I also collected some river mud from a nearby stream to ensure a rich bacterial variety in the kokedama. To be honest, you could just use universal soil since these bacteria are everywhere, but I wanted to give it an extra boost.

Electrodes – I used graphite rods from inside AA batteries (I add a video where I show how to extract them).

Plants – I used a small fern and a succulent, plus moss to wrap the kokedama.

Thread – to tie the kokedama together.

Wires and connectors – to connect the electrodes and measure the electricity generated.

Saline solution (salt and water) – to enhance conductivity, plus KCl for the membrane.

To create the mold with Agar Agar, I used a glass and a jar filled with water. The jar must fit inside the glass, leaving enough space between the walls for the Agar Agar.

We’ll test how much water we need for the mold before starting (this helps to calculate the right proportions of KCl and Agar Agar. This relation is: for every 50ml of water, 3.78g of Potassium Chloride (KCl) + 3g of Agar Agar).

Once we know the volume of water needed, we’ll add the KCl and stir until it’s completely dissolved. Then, we’ll start heating the solution.

Before it reaches a full boil (and make sure it doesn’t boil throughout the process!), we’ll add the Agar Agar and keep stirring until the mixture starts to thicken (this takes about 1 to 3 minutes).

While the mixture is still hot, pour it into the glass and then carefully insert the jar in the center. Now, let it cool and set.

When the Agar Agar is fully cooled and firm, it’s time to remove the mold. This step is delicate—be careful not to crack or damage the mold, as it needs to be completely watertight for our bio-cell.

Finally, test the mold by filling it with water to make sure it doesn’t leak.

We will start making the kokedama by mixing regular garden soil (universal substrate), organic matter and river mud. It is easier to do if the soil has a mud texture, so it is advisable to add water.

Once we have the mixture made, we will take the agar agar mold and put a first layer of soil on it. Then we will put the electrodes that we will have previously connected to a cable using connectors.

We will place the mold with the electrodes on top of the moss to make it easier to assemble the kokedama.

We will continue adding a little more soil mix and the plants.

Finally, we will secure all the moss and kokedama with thread and tighten it so that it remains firm.

At this point, it's time to fill the mold with saline solution. This saline solution is made with water and common salt in a 2% solution.

I used the bottom of a mold that went wrong as a lid to which I attached the electrodes.

We cover the mold ensuring that the electrodes are submerged in the saline solution.

Before testing to see if it generates electricity, we put the cables together (the two red ones, positive; and the two black ones, negative) on a terminal block to make it easier to test.

We will use a multimeter to test how much electricity is being generated.

It works! When the kokedama is finished, it's generating around 330 millivolts. We'll need to monitor it over the next few days to see if this value increases, stays the same, or decreases.

In the future I will try to make more kokedamas or pots following this style of cell, to make series and parallel connections to try to get a useful voltage.

To be continued...