Wednesday, August 21, 2013

Yellow leaves in my Aquaponics

Iron deficiency is one of the most common deficiencies in an aquaponics garden, it is responsible for the yellowing of plant leaves. Furtunately, this Iron deficiency is also one of the easiest problems to fix: simply adding a small amount of Chelated Iron fertilizer at regular intervals is all that is needed.
Iron deficiency in an aquaponics garden is quite common. In aquaponics, unless you add additional sources for the nutrients, all nutrients that come into the system will come through the fish food. Not all trace elements are introduced in the fish food.

Yellow leaves Aquaponics
Yellow leaves Aquaponics

Once you have run your aquaponics system for some time, you can quickly and easily tell if the plants are showing iron deficiency just by looking at them. When the plants have a slight yellowing of the leaves this is a strong indication for iron deficiancy. If it is left untreated, the yellowing of the leaves will become more pronounced. Plants generally react really well when the missing nutrients are introduced into the system and you should expect to see a result within a couple of days.

What is "Chelated Iron"?

Chelated means that the Iron has been chemically altered so that it is possible for the Iron the be dissolved in the water. You cannot simply through a bunch of Iron nails somewhere in the system and expect the Iron to somehow dissolve (it will dissolve very slightly if your water is acidic, but you don't want it to be too acidic).

It usually comes in a powder form, and it is a yellow powder. Often, some spoon or other measuring device is included in the pack. Some shops will sell chelated iron as a liquid, but this usually turns out to me much more expensive per gram of iron. Check the labels and compare prices between powdered and dissolved chelated iron fertilizer to ensure the optimal deal.

Buying Chelated Iron

You can buy this product in virtually every plant shop, it is very common indeed. It is quite expensive, it usually costs around $20 and will last in a small DIY homesystem for approximately one year. You can also buy it in a number of online webshops that will ship it to you in bulk if you require larger amounts of cheaper Chelated Iron fertilizer, for example if you operate a very large aquaponics system.

How much and how often?

Don't add too much of anything in one go in an aquaponics system. Adding about one teaspoon full at one time should be sufficient. You will have to add it about once every month.

Where to add it in the system

Murray Hallam suggests adding the Chelated Iron in the autosiphon of the aquaponics plant bed. The chelated iron will dissolve there and the pumps will bring it into the plant beds.

Is it safe? Will it hurt the fish?

Yes it is safe. No, the Chelated Iron fertilizer will not hurt the fish. Just avoid adding an massive amount of Chilated Iron fertilizer to the system. Also avoid adding it directly into the fish tank, the fish might mistake the powder for fish food.

Aquaponics, ækwəˈpɒnɨks, pisciponics