And why do you want to apply that particular product?

And because I always ask, where do you live?

I want to apply the liquid iron product for a quick dark green look. I live in Montreal Canada and the temps will be lowering soon below 80 degrees

I have Kentucky bluegrasss

Start at 2.5 oz ferrous sulfate per thousand and see how that does. Dissolve in water and add to your sprayer. Add some dish soap to the mix as well, then spray. Watch the concrete, it stains.

Good answers. Thanks. The same chemical is used to control snails and slugs, so if you were doing that, the answer might have been different. Had you lived somewhere where the soil was pure limestone, then ferrous sulfate doesn't work very well to green things up.

Lawniac, do I need to fill up the bottle ? How about the dial setting? I have it set to 3 now

Actually a different chemical compound than is the slug bait - that is iron phosphate ( FePO₄). Ferrous sulfate is FeO₄S.

Hose-end sprayers generally take the resulting mix and dilute it--something you don't want to do too much with iron sulfate.

Backpack sprayers (or a one gallon sprayer for something your size!) work far better for this purpose, and you may (read: probably will) be disappointed with the results using a Gilmour diluting this down too far.

You can set the sprayer way up, but then you're going to chew through iron sulfate and still not get a great result.

Optimally, 2 to 5 oz of ferrous sulfate per gallon of water (and a bit of soap to make it stick) are best per thousand square feet. With your KBG, go toward the high end--and don't worry if you over-shoot. Fescues can go battleship gray and take a while to fade back. KBG usually doesn't.

Lawniac, do I need to fill up the bottle ? How about the dial setting? I have it set to 3 now

Well now it's a matter of calibration. Whether you fill the bottle half way and set the rate low, or fill the bottle all the way and double the rate, the end goal is to be able to cover your entire lawn with 2.5oz of ferrous sulfate. The rate at which the sprayer will dispense the product from the bottle depends on the setting but also on water pressure from your hose and walking speed. My suggestion would be to fill the bottle with water and do a couple of practice runs to see which setting best allows you to cover your entire lawn with the entire contents of the bottle.

All of the formulas are not much good, unless you know the concentration of original Ferrous Sulfate Solution. Obviously if it is a 25% Ferrous sulfate solution will have a different mixing formula than if it is 5%.

Dumb question: What are the instruction of the original Ferrous Sulfate label for the application you are going to be doing?

I bought a ziplock bag on ebay and there were no instructions

So you are talking about 100% pure Ferrous Sulfate. ie a dry powder?

What color is it? Ferrous Sulfate with be a light blue crystals. Ferric Sulfate will be red to orange crystals. The percent Iron in the crystal is different.

Assuming you have 100% crystals of Ferrous Sulfate, try this site.

https://www.greenwaybiotech.com/products/ferrous-sulfate
https://www.greenwaybiotech.com/pages/ferrous-sulfate-iron-sulfate-faq

@gargengal: Minor quibble, but ferrous sulfate is FeSO4. The anion is not typically written as "O4S."

Krnuttle, its exactly what you have in your links. Thanks for providing this.

Gardengal, you're thinking of Sluggo. I'm thinking of DIY. Try it sometime. A better DIY slug/snail control is ammonium sulfate, but that's off this topic.

Hi, so I added 4 ounces of ferrous sulfate and 3 ounces of ammonium sulfate to 1 gallon and applied to the lawn last night using a backback sprayer. I applied to 700 square feet . Its currently raining and I dont see any difference at all. Should this take effect right away or does it take several days for the lawn to appear darker?

The only thing that happens instantly are usually not in nature. I have no experience with iron and grass, but I doubt if you will see much difference the morning after you apply the Ferrous Sulfate. My guess is it is going to take some sun shine and a couple of days before any change is noticed.

I sprayed iron on the lawn a few years ago and it didn't do anything at all that I could tell. Better to get your pH in the best spot if possible so the iron that is already there becomes available.

Ph is 6.7

Not bad then. I took it that you sprayed only part of the lawn so you can see a sort of before and after comparison? Any improvement yet?

All else optimal (more on that later) an extremely good eye can detect the color difference in the first area sprayed about the time you finish the last area sprayed on a larger lawn. Within a day, absolutely.

All else isn't usually optimal. Fast chlorophyll production requires easy access to plenty of elements, most notably magnesium. If your soil has optimal magnesium levels, you're fine. If not, enhancing those would certainly enhance the ease with which your grass (and all other plants) produce chlorophyll.

I often spray ferrous sulfate mixed with Miracle Gro (it has everything) or my home brew (mostly nitrogen) and just a pinch of Epsom salt (magnesium sulfate) per gallon just in case. My magnesium levels are completely optimal so the Epsom salt is overkill but makes me feel better and a pinch won't mis-balance even a pot of soil, much less a thousand square feet.

The ferrous sulfate application did absolutely nothing.

Can i use Miracle Grow (how much per gallon) if I dont know my Magnesium levels? I dont have the Miracle Grow "lawn food" available locally, we only have the "plant food" version.

https://www.walmart.ca/en/ip/miracle-gro-water-soluble-all-purpose-plant-food-24-8-16-171kg/6000036233000

Is this ok?difference?

I use the plant food, so that's cool.

" The ferrous sulfate application did absolutely nothing. "

First, let's analyze that. How many ounces of ferrous sulfate did you put down per thousand square feet? And did you use a surfactant of some sort to make it stick to the leaves?

If the answer was a reasonable amount on both (2-6 oz of iron, a dollop to an ounce of surfactant), then something's not optimal otherwise. Adding a pinch of Epsom salt per gallon and "some" Miracle Gro (I add about half a baggie per thousand square feet) might help.

If not, you may have another limiting factor that's keeping your grass from greening, up to and including the genetics of the grasses themselves.

I did not use an ounce of dish soap so ill try that with Miracle grow and epsom salt.

Mario, do you have any photos of your lawn handy? Maybe you can post a "before" photo here and then an "after" later on. I'm curious how green or "not green" your lawn is.