Backyard Aquaponics
A place to discuss aquaponics

I have a new system, 250gal IBC (500L?), fully cycled, stocked with about 30 tilapia juveniles. My plants are starting to show yellowing leaves, while the veins remain dark green. My tomato seedlings have some minor spotting on the leaves as well. My reading suggests iron or manganese deficiency.

My plants look a lot like this (from another thread, not my system):
viewtopic.php?f=3&t=21774

I don't have as many veins as the top picture in that thread, but I don't have plants that have that kind of vein structure.

Can someone rule out manganese deficiency from the pictures and description? If it is Iron deficiency, is it acceptable to use granular ferric oxide (GFO) to add iron to the system? I ask because I have some for my reef tank, and can get it in the system today. GFO is iron oxide hydroxide.

Here's some info:
http://www.reefkeeping.com/issues/2004-11/rhf/

If I use the GFO, I'm thinking of using about 4 teaspoons.

I'm growing Romaine, tomatoes, spinach, and kale. I will try to post a picture of the plants tonight after work if my description hasn't been enough.

I have a similar thing going on with the plants in my system, the advice I was given was to wait it out and let the system do it's thing, as it is only 5 weeks old.

I'm almost sure it is iron deficiency, but I'm wanting to stay away from adding anything to my system for as long as I can...

PH is the best method for making other nutrients available.

I don't have iron problems when my PH is down near 6. but I have other problems. Lettuce and bok choy don't mind though.

ha ha imagine my surprise coming on this thread hoping for answers and seeing my pics as an example made me chuckle my system is also around 5 weeks old and not even fully cycled think im guna get some maxicrop in there and hope for the best until i get some fish in there


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My tomatoes look exactly like yours .

My system was fishless cycle for 6 weeks, and 2 weeks with fish in it. Typical parameters are within normal limits, so I'm wondering about trace elements.

The system I got the fish from had mostly yellow-green plants, and they looked like too much water and not enough nitrogen. But, I'm new to AP vs soil, so I don't know what to do to not screw everything up this first season.

I guess asking more experienced folks is a good start.

I'm not sure but as far as the plants, I don't think it would help unless your pH is below 7. Provided this is a bio-available form, I would expect better results from spraying this on. I sort of think it's not available to plants in it's current form based on this information -

http://edis.ifas.ufl.edu/ss555

hi thoughtcrime

What's your systems PH, this will dictate which minerals your plants will be able to take up. There no point in adding anything if it wont be available for the plants.

6.9-7.1. Both of my test methods put it between 6.8 & 7.2 (as in, not either of those values).

I ordered DTPA last night and also gently washed the NFT tray roots with the light shower setting on my hose.

Luckily, the plants are still making new leaves (for now), so maybe that will buy me a little time to get the water params dialed in.

The Fe-DTPA should work. At your pH Maxicrop plus Iron would also work.