I don't know the answer to whether adding iron is "anti-organic" or not.

There can be a reason not to add iron during warm weather, but I think it depends on how it's added. If you're adding something like iron sucrate, greensand or some granular form of iron (iron sulfate, for example), I don't think it's an issue.

If you're spraying a water soluble form for a foliar spray to get a really fast green-up, the iron can cause burning if the temperature is over about 80 degrees. I haven't done this on the lawn, so it may not be as much of a problem with grass, but I know it can be a problem with trees and bushes.

BPGreen is correct. The type of iron is paramount. IMO, chelated iron is the best form for turf. Here's a link but it's not an endorsement for this particular product or manufacturer.

Chelated Iron

Since iron is naturally occurring and is not specifically banned on the NOP list, it can be used in organic farming.

Before the bashing begins -- yes, iron is a heavy metal. It also is a necessary element for most forms of life on this planet including humans.

Milorganite contains 4% chelated iron. No bashing on this either...been there - done that.

-Deerslayer

Greensand is the only source of iron that works in my soil. I can use Ironite all day long and get nothing.

Here is a link to a publication from Colorado State's extension service. Colorado has similar conditions to Utah, so most of what is in there is applicable to my situation.

I have a maple tree that used to be bright yellow, and I thought it was going to die for sure. I used about 50 lbs of sulfur poured in holes made with a bulb auger, and frequent topdressing with compost, shredded tree limbs, coffee grounds, etc, and it was green last year and looks like it'll be green again this year.

Deerslayer--do you know whether that's EDTA or EDDHA chelated iron? The EDTA iron doesn't help where I am.

David--I've never been able to find greensand around here. I could buy it online, but it's heavy, so shipping is pretty steep. I don't think ironite would help me, either. I think only a very small amount (if any) of its iron is chelated. And if it is chelated, I doubt very highly that it's eddha chelated.

I've never done anything to try to add more iron to the lawn. EDDHA chelate would be cost prohibitive. I've only seen iron sucrate as an additive in small bags of fertilizer (like 2 lb bags), so it would be impractical on a lawn, also. With the possible exception of greensand, none of the other iron supplements would help me.

Greensand might work, but I just checked around a little, and it looks like I'd need about 200 lbs for 4k sq ft. Judging from the places that show their shipping costs, it would cost me several hundred dollars to get enough for my lawn. Garden-Ville has pretty good prices but doesn't show their shipping costs. Too bad the only times I get to Texas I fly. If I drove, I could bring some back with me.

Is it "anti-organic"?

I don't think so, but I'm so not a purist. If I can't pronounce the chemical name and have at least a faint clue as to what the molecule might look like, I start to wonder. I may still use it, but I do want to know the side effects.

As far as anti-organic. Er, well, Aluminum is not a heavy metal and it is a poison (in large amounts). Let's not even discuss Sodium...blech! Iron is heavier and moderate amounts are essential for life. We could argue about the definition of heavy metals all day (to an astrochemist, anything heavier than Helium is a heavy metal).

I used greensand (available at my local garden store for a small fortune), 400 pounds/7 K square feet. In Pennsylvania's slightly acid soil the greenup was noticeable although very slow.

I do apply Milorganite for iron as well. I consider that to be a quasi-organic--close enough for me, not close enough for many purists.

I, personally, wouldn't touch Scott's Turf Builder with the proverbial 10 foot pole. I also don't criticize those who do use it (my [quasi] organic choices are my own, not yours, and it's not like it's a poison), and it does have some iron in it.

Unless I miss my guess, in TX the soil's pretty alkaline? If so, what I do here in a pH range of 5.5 to 6.8 may not work well for you.

Texas' ph soil varies. For an example, if you go to houston, where ph is neutral to slightly acidic (lots of pine trees there) go straight up north and eastward, it's mostly sandy and the pH is on the acidic side. Westward, it's alkaline except for pockets of acidic soils.

I'm able to get greensand dirt cheap up here so I am fortunate for that.

Adding iron chelates is a terrific way to green up a lawn, especially in the cooler times of the year, when soil iron tends to be tied up in the soil.

ANYone who knows how to grow a pretty Centipede lawn (yes, I mean pretty) knows that iron is a key element for that species, in particular.

"Deerslayer--do you know whether that's EDTA or EDDHA chelated iron? The EDTA iron doesn't help where I am."

I've only used EDTA. Chelated iron works well in Northern Illinois (slightly acidic, loam soil). I agree that chelated iron may not work well with different PH and soil types. The amounts of various trace minerals may also affect its uptake.

-Deerslayer

Thanks for all the imput guys. And, yes, here we have high alkalinity clay and iron tends to bind up in it.

I've got a crowd coming in for a wedding mid-July. I didn't want to fertilize my cool season grasses around that time because I didn't want to encourage growth in the middle of the summer.

But, giving it a shot of greensand a couple of weeks ahead of time ought to let it show to best advantage without a splurge of growth.

Chelated iron can be applied as a spray and it will be taken up by the foliage. The technique is often used on golf courses a couple of days before a big event. Liquid chelated Fe products are readily available.

Rhizo--Is it safe to spray the liquid chelated iron on a lawn in the heat of summer? I know spraying on trees causes burn, but I don't know whether it affects grass the same, or not.

Lesco has several liquid chelated iron products. Search the Lesco site for "chelated".

I'm interested in rhizo's response. I haven't applied FE during high temperatures.

-Deerslayer