I thought I’d share with you a question I got from a reader last week that strikes me as something that a lot of people probably wonder about:
Here is the question I’ve always wondered/worried about with aquaponics: What about soil nutrients?
The more I read about organic/holistic gardening, the more I realize the importance of the soil and its bio-nutrients and how much we don’t understand everything they do. So do we lose something when we move to water?
Thanks Chelsea for your great question!
Aquaponic systems are actually teeming with bio-nutrients, micro-nutrients, and probably all sorts of things we don’t even know about yet!
Soil is one medium for supporting communities of micro-organisms and transporting nutrients. Aquaponic grow beds filled gravel and oxygenated water is another. My system actually has worms living in it.
Aquaponics may be somewhat lacking in mycorrhizal fungi
since they require a stable medium, though I’m not actually 100% sure that’s true. The primary effect that we know of for mychorrhizae is that they extend the reach of roots into the soil and bring back nutrients for exchange with plant sugars.
In aquaponics, this may not be necessary since all the nutrients are soluble, and the roots go so entirely nuts that we sometimes have to trim them so they don’t clog all the pipes.
That issue is actually one that drove a lot of people to aquaponics from hydroponics. There have been some interesting studies done comparing the two. What they’ve found is that, even though aquaponics has about 1/10 the concentration of the major nutrients we know about (NPK and a few others), plants actually grow slightly faster
. It appears to have something to do with the intense bacterial life found in aquaponic systems, though nobody understands all that well enough yet to explain it.
Plants grow anywhere between 40% faster to 4 times faster
than in in aquaponics than soil, depending on the plant, the system, and the weather.
Courtesy of Ecofilms
Soil life is so far beyond human understanding right now that we can do little more than scratch our heads and do what works.
Aquaponics tries to use and encourage the kinds of complex living system that we find in soil, in a way that hydroponics and chemical gardening don’t. Whether it’s similar or the same as what we find in soil, at this point is anyone’s guess.
What do you think – is aquaponics natural?