How does an aquaponic system generate NPK for plants?

[Pravind Fisher]

How does an aquaponic system generate NPK for plants? If yes is it sufficiently produced?

[Jonathan Kadish NYC AA Chair]

Aquaponics takes advantage of the Nitrogen Cycle that is found in nature. Fish are fed food which has many minerals and elements already in it including the P and K. Fish poo begins to decay and break down through natural processes. Ammonia is a byproduct of the decay, as well as secreted by the fish through their gills. This ammonia is used by bacteria for energy and the byproduct of the bacteria is Nitrate which the plants use to grow.

[TCLynx]

The Aquaponics system doesn't in and of itself produce NPK.  You feed the fish and the wastes from feeding the fish are converted to NPK by biological processes.  You might also get some nutrients from your source water and from buffering agents to keep pH in balance as well as some people might occasionally use some seaweed extract or other trace element sources to supplement their systems.

Does it produce it in sufficient quantity, well only if you have a balanced system with an appropriate amount of fish being fed a high quality feed to support the amount of plants you have for any given season.  It doesn't actually take a huge amount of fish to feed a good amount of plants.  How fast the plants use the nutrients will also affect the balance so the type of plants will cause this to vary.  You have to grow alot more lettuce to equal the nutrient usage of a few huge tomato plants.

It is all about balance but this balance can be achieved, it sometimes takes a bit of patience.

[Jon Parr]

Vlad just started a discussion that concerns this, Pravind.

Check it out: http://aquaponicscommunity.com/group/fish-less-systems/forum/topics...