Iron deficiency

[Chandara Khan]

Hi everyone! I need your help. I have run my raft system for about 2 weeks and now some of my tomato cucumber and lettuce leaves turn from green to yellow. Is it right saying that my plants are having iron deficiency? To solve this problem some documents recommend using Iron chelate. Unfortunately, iron chelate is not available in my country ( Cambodia). Anyway, I've found another product which is mainly composed of Zine (a type of metal). Can zine help me solve this problem. Can it replace iron chelate or not?

[Jonathan Farrand]

check out www.farmerbrownsaquaponics.blogspot.com/2011/01/molasses-chelator.html

Rusty Metal!!

[TCLynx]

More information would help to know if you are suffering iron deficiency or not.  Are the leaves that are turning yellow the top new leaves or the oldest leaves first?  Are the veins staying green longer than the rest of the leaf?

 

Iron deficiency is often not because of lack or iron but actually from pH lock out.  What is your system pH?

[Chandara Khan]

Oh thank  TCLynx and Jonathan! Well, my pH is around 7.2 and I think it doesn't matter with the pH. Anyway I think my plants may be facing nutrient deficiency or iron deficiency since the system has just been set up for over two weeks. What do you think TCLynx? Regarding yellow leaves, I notice some leaves are yellow while the others are green. I'll post some  pictures of them. Thanks

[TCLynx]

Well let us know if it is the newest growth that is turning yellow first or the older lower leaves turning yellow.  Iron deficiency shows as the newest leaves yellowing first but their veins stay green.  Be careful of any metal supplement that has zinc or copper in it.

But  good chance it is just cause the system is new.

Where are you at in the cycling of the system?  What are your ammonia, nitrite and nitrate readings?

 

I might suggest adding a little maxicrop (or whatever seaweed extract you can find there, you want the stuff that has the NPK numbers of 0.1-0-1 ) for some kick start of the trace elements and not worry too much about the deficiency till the system finishes cycling up.

[Chandara Khan]

Ok thank TCLynx! I see what you mean. I'll show the pictures of my plants and the result of the 3 Ns tomorrow. Anyway why should i be careful with using any metal supplement that has zinc or copper in it?

 

[TCLynx]

zinc and copper can build up to toxic levels for the fish pretty quickly if you are not very very careful.  And there are other metals that are bad too.

[Johann]

To much copper will kill fish and the roots of plants, like rootkiller (coppersulphate).

Same as zinc.

Chandara Khan said:

Ok thank TCLynx! I see what you mean. I'll show the pictures of my plants and the result of the 3 Ns tomorrow. Anyway why should i be careful with using any metal supplement that has zinc or copper in it?

 

[wes]

Just to add to the possible issues if this system is only 2 weeks running total what are your Nitrates levels at?? have you completed a full cycle of the system or is it still in this process???  Sorry TCLynx didnt read all the posts, you have already covered this part.

[Jon Baldwin]

ph at 7.2 is exactly what Murray Hallum (sp?) shows 24 minutes into his "aquaponics secrets" vid.  paraphrasing, but he says that often in new systems you get ph lockout due to the grow bed going anaerobic.  need to get more O2 to that part of the grow bed.

[Allisyn Wood]

My system has been up and running with fish for a few months now.  My levels are where they should be.  My older tomato leaves are turning yellow first. Started about a week ago.  Suggestions? 

TCLynx said:

Well let us know if it is the newest growth that is turning yellow first or the older lower leaves turning yellow.  Iron deficiency shows as the newest leaves yellowing first but their veins stay green.  Be careful of any metal supplement that has zinc or copper in it.

But  good chance it is just cause the system is new.

Where are you at in the cycling of the system?  What are your ammonia, nitrite and nitrate readings?

 

I might suggest adding a little maxicrop (or whatever seaweed extract you can find there, you want the stuff that has the NPK numbers of 0.1-0-1 ) for some kick start of the trace elements and not worry too much about the deficiency till the system finishes cycling up.

[Nate Storey]

I'll repeat what TC said- many of the non chel. Fe supp.s have other metals that can be harmful to your system and difficult to remove- including lead, selenium and other heavy metals.  I recommend staying away from non chel. Fe supp.s for that reason.  at 7.2 you'll probaby have iron availability issues- the most basic thing to attempt some in-system iron chelation is to plant rye-grass in a bed.  Grasses like rye can synthesize chelatins that bind to iron and make it plant available at higher pHs.   It takes up room nothing is guaranteed, but if chel. Fe isn't available to you, it's worth a try.  I guess if you need it you can always get someone coming from somewhere else to bring some along- a 10 lb bag has lasted me years for my 4000 gal. of system- so it lasts a while.

 

Allisyn- you need iron, most likely.  You can find chel. Fe at your local hardware/lawn and garden store.

[TCLynx]

You say your levels are what they should be?  What does that mean?  What is your Nitrate level?  Older leaves yellowing could be a sign of nitrogen deficiency but I've noticed that tomato plants do tend to sacrifice their older leaves in favor of new growth even in systems with plenty of nitrogen. 

Allisyn Wood said:

My system has been up and running with fish for a few months now.  My levels are where they should be.  My older tomato leaves are turning yellow first. Started about a week ago.  Suggestions?