Mineralized Soil Substrate by Aaron Talbot

Mineralized Soil Substrate: by Aaron Talbot

Over the years dedicated aquatic plant hobbyists have developed many different methods to maintain vibrant freshwater flora. After having tried almost all of the popular fertilization techniques, I have finally found one that produces consistently healthy aquatic plants. That fertilization method imparts essential nutrients by using mineralized topsoil as a substrate.

When I joined the Greater Washington Aquatic Plant Association about four years ago, I attended my first official meeting at the home of Sean Murphy. Sean is a Fisheries Biologist by trade and has been employing mineralized soil in his planted aquariums for nearly two decades now. He developed a “recipe” for the soil substrate during his collegiate studies of wetlands soils. It is his recipe that I have recently begun using with great success.

Using topsoil or potting soil as a substrate is not a new idea. Aquarists have been using this method to grow healthy aquatic plants for decades. However, this method does seem to pose some problems, namely algae outbreaks resulting from light intensity that is too strong. This is especially true when you first set up your aquarium with this type of substrate. The algae likely results from the excess nutrients that decomposing organic materials release in the soil. The decomposing organic materials are not bio-available to the aquatic plants. As the tank matures, the algae dissipate slowly as the organics in the soil finish breaking down.

Mineralizing the soil beforehand helps to speed the breakdown of organic materials in the soil. In turn the mineralized soil will help shorten the initial algae outbreak period that many aquarists experience when using a soil substrate. Soil mineralization occurs from exposing bacteria, enzymes and other soil microbes to oxygen in a moist environment. The microbes break down the organic materials in the soil into bio-available minerals. As an added bonus these new bio-available forms of nutrients are generally only available to plants and not to algae.

There are a few other components to the mineralized soil recipe. Clay provides a source of iron. The clay also serves to bind with the soil as a flocculating agent. When plants are uprooted or disturbed, the added clay will help the soil to settle back to the bottom of the tank. Adding Dolomite to the base of the substrate will provide plants with the necessary calcium and magnesium they need for healthy growth. The calcium and magnesium in the dolomite will also help to keep the soil from becoming too acidic. Lastly, add soluble potash for an initial potassium source.

It is still possible to use pressurized CO2 and high lighting with this method of fertilization. I have setup four tanks using this method and all of them have been high-tech setups using CO2 and high lighting. I rarely ever have to dose any supplements save for the occasional dose of potassium. Use caution when dosing and dose very little amounts at a time.

 

Thanks

Rick