Aquaponics and Iron

When I very first started learning about aquaponics I was under the misconception that if you kept the fish alive and happy the plants would automatically be happy.

How many of you have fallen for the mis-information touted by some who only want to sell you their aquaponics-related product?  They will tell you that an aquaponic garden is a totally closed system that only needs the addition of food for the fish.  I also read that aquaponic gardens require little to no care.  Pfffftttt.

My aquaponic gardens are in many ways more easier when it comes to care but they are not care-free.  One thing that is common to both aquaponic gardens and soil gardens is chlorosis, or a need for iron.  Because the deficiency interferes with chlorophyll it is fairly easy to spot.  The leaves will become light yellow but stay dark around the veins.

 Iron in Aquaponics Explained by Nate Storey is a great place to learn exactly how iron acts in an aquaponic situation.  In a nutshell iron may be unavailable in aerobic situations.  Since growing with aquaponics is aerobic, you need to dose with iron on a regular basis.

Here is a picture of one of my sweet basils that needed a dose of iron.  As you can see, other than the color of the leaves the plant looks "normal".  Tthis is not healthy for the plant but it is common in aquaponic gardens, especially if your pH gets on the high side of the scale.

I use Fe EDTA because it is available to the plants even in a high pH situation.  This isn't true if you use something like seaweed fertilizer.  I read lots of folks raving about seaweed fertilizer for their aquaponic systems but I don't see iron (either present or in a form available to the plants) ever listed on the label.

The Fe EDTA I use is just the iron in a 6% strength.  It works.  It is not terribly expensive.

Just look at how this basil responds in just a few days.  Hard to believe that is the same plant isn't it?  Looks much more tasty to me! 

Basil After Iron

The "experts" say to dose your aquaponic system on a regular basis with iron.  I only dose my system at home when it shows signs of chlorosis.  At the Together We Stand gardens, we dose about once a month because the pH of the water stays high.

Aquaponic gardens can be easier than gardening with soil, but it still requires your attention.  You just don't have to weed and water!  Instead you have to do things like feed the fish and monitor water quality for ammonia, nitrites and nitrates.