The Nitrogen Cycle

This is one of the few scientific parts of the aquaponics process and it is not too complicated for someone with no technical background to understand. Put very simply, the process is underpinned by some serious science but we only need to know a few things about the nitrogen cycle: 

1. It starts with ammonia
2. Bacteria break the ammonia down into nitrites and 
3. Other bacteria break those nitrites down into nitrates which are plant food. 

That covers the nitrogen cycle.

Although there is a lot to learn when starting on your aquaponics venture none of it will be overwhelming or too technical. Part of the joy of growing your own vegetables and fish is that you’re getting back to nature. Although aquaponics is a science based process the act of growing vegetables and fish are the same. You need to grow fish in clean water where they can thrive and they need a good nutrient rich feed, usually in the form of pellets. You need to plant vegetables in a substrate that can support them and they need water and food, mainly in the form of nitrates.

The nitrogen cycle is an integral part of the aquaponics process. The waste from the fish is transported to the grow beds (by pumping water into the grow bed) which contain gravel or clay balls. This waste is then slowly filtered through the grow bed media. During this process the fish waste, which consists mainly of ammonia, comes into contact with bacteria that has taken up residence in the grow bed media. This is where the magic happens.

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So where do these magical bacteria come from? How do you find them? Well you don’t need to. One of the most exciting components of aquaponics is your free bacteria colony. If you provide a continuing source of ammonia and a substrate (like gravel or clay balls) in your system the bacteria will arrive without invitation. They will multiply rapidly and start working hard for you to provide life-giving nitrates to your plants growing above them in the gravel. Once your nitrogen cycle is fully operational and your bacteria colony has grown to the proper size your system is said to be “cycled”. We will discuss cycling your system in a later article.

Another exciting element of this journey is that the bacteria colony grows or shrinks according to the level of ammonia in the system. A small system will have a small bacteria colony and a big system will have a bigger bacteria colony. The size of the colony is self-regulating depending on how much ammonia is available to process. If you have a small system that you decide to expand, guess what? You got it right – the colony will expand.

Just another one of the exciting benefits of growing your own food using aquaponics – the free bacteria colony.