Iron For Plants From Rusting Rebar ?

[Bradly]

I saw a post online where someone was placing rebar pieces into water and using it as a source of iron for the plants. It's an interesting idea.

Is rusting steel a good source of iron ?   Any input is much appreciated.

 

[Cadillac Snow]

In my very amateur opinion, I believe that the less you are able to control in your system accurately, is recipe for unwanted, or adverse reactions. I think, chelated iron powders, and trace element nutrients in the hydro solutions, I use, along with balls on accurate measuring, gives me a better sense of control over my system.

[Jonathan Kadish NYC AA Chair]

If I am remembering correctly, only certain forms of iron are useful to plants. Iron HEDTA (Chelated) is one of them.

[Bradly]

Cadillac...I'm with you on that point...that's why the idea of steel rusting at it's own speed/amounts made me uneasy.

In looking for Celated iron I found some being sold online by Green Leaf Aquariums, and sent inquiry as to whether or not theirs has any harmful metals or anything for fish...still waiting for answer.

(I had some chelated iron from H.Depot but I read that it has zinc in it so do not want to use that stuff).

Jonathan- my plants need some "greening" up as my system is new, have you heard or seen anyplace that sells Chelated iron that's safe for the fish??

Thanks both of you for the responses !!

[Keith Rowan]

you need chelated iron, putting some rebar in won't help your plants.. you can order maxicrop with iron from amazon, lots of hydro shops carry it as well.. a little goes a long way

[George]

http://community.theaquaponicsource.com/forum/topics/chelated-iron-...

[Vlad Jovanovic]

HEDTA (2-hydroxyethyl)ethylenediamine triacetate...is only one of many chelating (i.e binding) agents used to keep iron in it's plant usable form. The only "form" of iron that is plant usable is Fe2+.

Rust is Fe3+ ...also called Ferric iron...and can also be written as Fe(III)...and can do nothing for plants.

Fe2+...also called Ferrous iron ...and can also be written as Fe(II) is, again, the only plant usable form of iron.

The chelating agent, be it HEDTA, EDTA, DTPA, or EDDHA (my personal preference) only serves to chelate (bind) the Fe2+ and keep it from reverting to Fe3+ once it hits an oxygen rich environment, and to keep the iron soluble as well I suppose.

If you want to obtain plant usable iron from rust in order to move away from industrial chelating agents, (and are committed enough to do so) you can...but it's no walk in the park. 

Also, not all chelates are created equally. EDTA has been proven quite some time ago to be toxic to plants, and very few serious hydro operations/growers will use it anymore...DTPA, suspected plant toxin, but not yet proven...blablabla...

If I'm not mistaken the iron portion of the MaxiCrop plus Iron, is iron ferrous sulfate (but anyone who cares might want to check to see if that is still the case)...sulfates come with their own set of problems for plants, but 'probably' not a concern at all in the quantities you'd use in a new AP system. Although recirculating systems are sooo much different than soil or run to waste hydro.....

Jonathan Kadish said:

If I am remembering correctly, only certain forms of iron are useful to plants. Iron HEDTA (Chelated) is one of them.

[Bradly]

Thanks Keith, I didn't know Maxicrop was used after system was cycled... I'll just order some.

George, thanks for the link ...very interesting reading... man-lots to learn

[Jonathan Kadish NYC AA Chair]

You can find it on amazon or ebay. I bought Grow More's Organic Based Iron Chelate on Amazon. Just make sure it is one of the good kind that Vlad mentioned.

Bradly said:

Cadillac...I'm with you on that point...that's why the idea of steel rusting at it's own speed/amounts made me uneasy.

In looking for Celated iron I found some being sold online by Green Leaf Aquariums, and sent inquiry as to whether or not theirs has any harmful metals or anything for fish...still waiting for answer.

(I had some chelated iron from H.Depot but I read that it has zinc in it so do not want to use that stuff).

Jonathan- my plants need some "greening" up as my system is new, have you heard or seen anyplace that sells Chelated iron that's safe for the fish??

Thanks both of you for the responses !!

[Vlad Jovanovic]

Oh yeah, I guess I'll say it again since I take issue with such bullshit, shiesty marketing/labeling ploys...

There is no such thing as an "Organic" (H)EDTA chelate, so when GrowMore's says "Organic Based Iron Chelate"..it would be just as correct for Shell Oil to say "Organic Based Gasoline" (which, while technically correct, is a kind shifty way to make us consumers (mis)believe that their particular product is somehow safer or 'more natural' than any other similar product. EDTA is EDTA and ferrous iron is ferrous iron. I'm not saying it's a bad product or anything...just that "calling bullshit" on their labeling practices. Notice they have the (legal) sense not to list any of the Iron Chelate products in the section labelled "Natural Organic Products" in their big catalog...

Some countries allow the controlled use of Fe-chelates to be used in Organic gardening (while others do not).

GrowMore makes a 10% Fe-(H)EDTA chelate (in the green and yellow packaging most folks seem to go for), but they also make a 6% Fe-EDDHA product (the purple packaging) that may seem a bit more expensive...

It may not matter a whole lot in reality, but when it comes to chemicals, toxins etc...people tend to become rather particular. I'd always go with an EDDHA product over EDTA or HEDTA if available.

[Rex Byrns]

I had an interesting discussion with the guy that gave me the tote for my fish tank.  He is a good chemist that is making tons of money right now in the plastics and oilfield industry.   The first de-greaser I ever saw him selling, he would drink. 

We discussed chelation and the fact that it is in fact non-organic chemistry and is commonly used around here to hide bad things like chromium.  Chelate comes from the greek word "claw".  Most methods if not all require that the process work down the element table to get to iron..  There can be elements hidden from testing, but still absorbable (if that is a word - lol).

Long story short.....   He recommended that I try 16 penny nails.   He thinks the plants will get it.

[Vlad Jovanovic]

Your chemist should know better than that... :)