Backyard Aquaponics
A place to discuss aquaponics

Hi everyone !

Currently trying to grow beans in my small indoor AP setup, and while parsley and a variety of arugula are doing just about ok , the rest not so much :
- the beans' leaves have started to become discolored/yellowish
- the veins still remain green
- not all plants/leaves are affected in the same way
- it seems to have gotten worse ever seems the first flowers came out

Based on the various posts and information I found I would venture that this is Iron deficiency but I am not entirely sure. Could this also be nutrient lock out ? Something else?

System is 80 x40 cm bed, 60 l aquarium with goldfish.

I am also trying to grow two zuchini plants in there, and they are also not doing great, but not showing the same symptoms: could I just be overtaxing the system ?

Thanks a lot in advance !

A few pictures of what is going on:

If those are new leaves with the yellowing between the veins then yes it's probably an iron deficiency. You may have a different deficiency on the bean plant to the left - probably either magnesium or potassium. Notice how the lower leaves are affected more than the upper which says that the nutrient is mobile within the plant. Iron is not which is why the deficiency would show in the new leaves.

I agree with Scotty - definitely iron and most likely potassium. Also, I know a lot of folks like to salt their systems, but beans are extremely sensitive to salt (along with strawberries) so make sure you aren't salting while trying to grow beans.

Fruiting plants typically require you to add supplements in order to have decent production. What pH is your system at? pH will heavily impact nutrient uptake.

@scotty435: Thanks for the feedback ! I took a closer look and interestingly the new leaves actually look healthy, it is just a set of older leaves that looks very pale/yellow so that is coherent with your analysis :
to get this right: so Iron deficiency would only show up in newer leaves because Iron does not circulate within the plant ?


@ebeuerle : Thanks for the information ! Would "salt" in that case be table salt , epsom salts or something else ?
Ph is usually around 7 to 7.2.
Given that all newer leaves now seem to be very healthy and the beans themselves are growing well , I wonder if I did not have a Nitrate spike when the leaves where yellowing. (although I feed low amounts regularly and try to be very careful with overfeeding)

Btw, I looked at various posts about deficiencies, but is there a wiki/knowledge base with more in depth explanation of the symptoms , biological reasons behind them & possible solutions ?

Marko - usually the salt that is added is pool salt or water softener salt since it typically doesn't have the anti-clumping chemicals added that most table salt does (NaCl). However, you can use CaCl or KCl for the same effect with a bonus of getting extra calcium or potassium. Epsom salts (MgSO4 * 7H2O) doesn't help fish (no chloride) but can be used for supplementing magnesium and sulfur.