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morpheuspa

Spray Iron on the Lawn

I make my own solution--4 ounces of ferrous sulfate monohydrate, dissolved outside the sprayer in a bucket with about 3 ounces of ammonium sulfate. Then I add that and water and surfactant to my sprayer to about a gallon and use that to cover 1,000 square feet.

Naturally, I discovered I'd used the last of my ammonium sulfate this year so I substituted Miracle Gro at about 1.5 ounces instead. That's fine.

Oh, and I'd run out of surfactant so ended up directly adding sodium lauryl sulfate powder to the sprayer and shaking the thing when it was on my back. That also was fine.

Oh, yeah, I was running out of time and daylight this evening, so it was a rush job, too. Er...OK, fine.

Yes, it was a comedy of errors.

What it does: iron applied to the lawn assists in chlorophyll production, darkening the color. It's temporary, but when temperatures are about to tumble to winter levels, "temporary" means "until early April." Since my lawn doesn't go dormant unless the weather is extreme, I expect that color to hold through the period except, perhaps, in February if temperatures get very cold.

The darkened color also absorbs more sunlight, helping the lawn to stay out of dormancy by photosynthesizing more carbohydrates and sending the signal that dormancy isn't worth it just yet. Plus the darkened color absorbs more heat, radiates more energy to the ground below, and keeps the entire lawn and soil profile warmer than it would otherwise be. Not by much, but I'll take it.

The ammonium sulfate/Miracle Gro supplies a tiny bit of nitrogen that also supports chlorophyll production. It doesn't set off any growth this late in the season and in amounts that small.

The surfactant, which can be anything from shampoo to sodium lauryl sulfate (I have it on-hand for soap making) helps the iron stick to and spread on the leaf without making tiny droplets and rolling off.

This can be applied to lawns, as well as any evergreens. I also apply this to my rhododendron, Thuja, and evergreen shrubs.

Comments (25)

  • forsheems
    9 years ago

    I've never applied any type of spray iron to my lawn. So far, Milo is the only iron it has seen and the color was very noticeable. With time running out and having very little free time right now they have a product at the local Tractor Supply called Master Gardener Liquid Quick Green. According to the label it is 1% Iron and 12.5% Humic. It's on clearance for $4.99 per quart and a quart covers 5k square feet.

    What are your thoughts on this product?

    Is 1% iron going to be enough to make a difference?

    Should the iron app be before or after the final winterizer app?

  • BoatDrinksq5
    9 years ago

    I always like to pickup cheap clearance items like that when I see them. Always has some core 'good ingredients', easy to apply, etc. Can make your own - but often the price is a wash or at least in the same ballpark. decent percent of humic, might be better for a late spring app to spark microbe growth.

    I don't know about that iron %, seems pretty low (could compare it to bonide iron).

    I thought theirs was 2-4%? hmmm it is still on amazon (discontinued)

    This post was edited by BoatDrinksQ5 on Wed, Nov 12, 14 at 11:38

  • danielj_2009
    9 years ago

    Morpheus, or should I say Morferrous, we are expecting the big chill to hit us in a day or two, as are you. Can you recommend anything relatively easy I might use to green up, or is it becoming too late? I haven't winterized yet of course. I know an iron treatment isn't really necessary, but if it can help a little, then why not?

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    >>I've never applied any type of spray iron to my lawn. So far, Milo is the only iron it has seen and the color was very noticeable. With time running out and having very little free time right now they have a product at the local Tractor Supply called Master Gardener Liquid Quick Green. According to the label it is 1% Iron and 12.5% Humic. It's on clearance for $4.99 per quart and a quart covers 5k square feet.
    What are your thoughts on this product? Is 1% iron going to be enough to make a difference?

    The percentage of iron seems really low. Bonide's iron spray is 5% iron, and I consider that to be fine, but I can do better at home in a bucket.

    If you're happy with the color from the Milo, I'd say that's great. Clearly you're not iron short.

    Neither am I, I just like the boost of dark green color for winter.

    >>but often the price is a wash or at least in the same ballpark.

    It does depend. I got ferrous sulfate monohydrate (harder to handle than heptahydrate but a slightly higher iron percentage by weight) for around $1 a pound. Soap, for me, costs zip as I make it myself and have tons of raw materials on hand at all times. Ammonium nitrate is cheap--Miracle Gro, not so much, but that was a substitute.

    Figuring 3 pounds across the 10,000 square foot lawn of iron, 1 pound of Miracle Gro, and about 0.2 ounces of sodium lauryl sulfate powder, the grand total cost to do the entire lawn (plus evergreens) was around $4.25.

    One bottle of Bonide is $8.50 or more, which will cover about 3,000 square feet if you stretch it.

    So homemade, in this instance, is one sixth the price and about twenty times the effort and annoyance (still relatively minimal).

  • BoatDrinksq5
    9 years ago

    Yes no doubt bulk purchasing the raw goods can't be beat if you plan on using the stuff regularly.

    I like cooking and good food... but sometimes it's nice to just put a frozen pizza in the oven with two working parents with a kid/dog/boat... :-)

    Also some products (SoilAmp, LiquidGold, Liquid Dethatchers etc) have some specialty ingredients(hypotheticly...) that it just doesn't pay to buy pounds worth of it and have it lay around for a one-two time time app. Not that i advocate paying market price for any of those RTU products.

    But as my lawn nerddom increases - the bags, boxes, and potions of goodies just keep increasing. spray iron just hasn't been at the top of the list just yet. milo seems to keep me happy.

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    It's weird, but so many of my lawn specialty stuff shares a common use in another hobby. Mostly soap making, but even with the electronic vaporizer items I used to quit smoking a few years ago (glycerin is a great humectant and finds some use as a water retention chemical in the gardens).

    >>Morpheus, or should I say Morferrous, we are expecting the big chill to hit us in a day or two, as are you. Can you recommend anything relatively easy I might use to green up, or is it becoming too late? I haven't winterized yet of course. I know an iron treatment isn't really necessary, but if it can help a little, then why not?

    Sorry, I missed this!

    Bonide's Iron (#298 or #299, either pure iron or with other micros, which are just fine used once a year), will serve exactly the same purpose without sourcing a ton of items. Personally, I'd mix some Miracle Gro into the sprayer with the stuff for a touch of nitrogen, but that's just me and it isn't necessary.

    I'd also add an ounce of soap per gallon to get it to stick better.

    Add to your sprayer and spray on the lawn.

  • danielj_2009
    9 years ago

    Cool, thanks for the Bonide tip!

  • danielj_2009
    9 years ago

    ok not to seem co-dependent here but how about Ironite, which is a pellet? This product is a bit more pricey than I am willing to pay just for a little extra iron green up. However it made me wonder whether the liquid iron form is beneficial at this time of year rather than the pellet?Is the liquid spray more a matter of getting the iron into the leaf as quickly as possible?

    Of course the Home Depot guy has been a landscaper for 30 years and made sure to tell me about how the lawn should turn yellow this time of year and how I should only consider adding lime at this point. Oh well I guess I am just another dumb homeowner.

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    >>ok not to seem co-dependent here but how about Ironite, which is a pellet?

    Never. Milorganite is cheaper per pound, contains almost the same iron, also contains organic material, and doesn't contain arsenic compounds, half of which have been found to be water-soluble by mass.

    In a competition, Milo would win at twice the price.

    But if you'd rather use more Milo, you can do that instead. It's slower, won't produce the same dark green, and having organic feedings freeze up top isn't a great idea in late fall and into winter.

    >>f course the Home Depot guy has been a landscaper for 30 years and made sure to tell me about how the lawn should turn yellow this time of year and how I should only consider adding lime at this point. Oh well I guess I am just another dumb homeowner.

    So he's telling you that he wasn't a very good landscaper...obvious by the fact that he actually works at Home Depot and not as a landscaper.

    Browns are normal if the grass is going into dormancy (but that can be avoided). Yellow is not a normal color.

    Yellow happens because the colder, wetter soil is unable to feed iron to the grass' roots as fast as the grass needs it. So the grass gets chlorotic.

    The ways around that are lots of organic matter (doesn't waterlog very easily, plus holds tons of iron and lets it go more easily than soils do), increasing overall iron, and deepening the grass roots to the point that even reduced absorption is sufficient due to the grass' root area.

    The quick way around it is just to spray iron.

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    Well, the color change is disappointing so far. But that's mostly because the color I started with was already very dark green.

    Dropping temperatures tomorrow will increase the color change, and of course the rapidly developing contrast between my dark green lawn and the neighbors' tan ones will also help it look better. :-)

  • danielj_2009
    9 years ago

    Morpheus - your depth of knowledge on this stuff is amazing! You've clearly been at this for awhile and have actually tried out different ideas in the field. I had the same thoughts about the Home Depot landscaper.

    Just to be clear, though. Does liquid iron get absorbed directly into the leaf blade, rather than going up through the roots in the case of something like Ironite? Is it because of the cold ground/root temps that you prefer to use liquid iron for the maximum green up you are looking for?

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    >>Morpheus - your depth of knowledge on this stuff is amazing! You've clearly been at this for awhile and have actually tried out different ideas in the field. I had the same thoughts about the Home Depot landscaper.

    I am...not a spring chicken, decidedly middle-aged. My oldest plant is nearly as old as I am and still looks great. I've been interested in plants since before I could read.

    My detractors claim I learned to read at the age of twenty-seven. This is not true.

    >>Just to be clear, though. Does liquid iron get absorbed directly into the leaf blade, rather than going up through the roots in the case of something like Ironite? Is it because of the cold ground/root temps that you prefer to use liquid iron for the maximum green up you are looking for?

    Liquid iron is a foliar application, and a free ion (ferrous sulfate is a salt). Uptake is through foliar absorption, and iron is required in such small amounts that even what the leaf can absorb is significant enough to cause a large color change if iron is needed.

    There's actually no case where liquid iron works more slowly or worse than soil-applied iron, although you can dump a lot more on the soil at any one time than you can get to cling to your leaves. So for changing actual soil numbers significantly and reasonably quickly, soil applications are necessary.

    Ferrous sulfate can also be soil applied in amounts up to about 3 pounds per thousand square feet, three times yearly (with a margin for error as the yearly max is about 10 pounds per thousand).

    The iron ion is very reactive, so it'll rapidly find a hydroxide split from water, or some oxygen kicking around and turn to a tightly bound compound that requires bacterial processing to flip back to an available iron ion. That processing works better the more acidic the soil, from practically zero above neutral to a heck of a lot at a pH of 4.5. That's why blueberries and rhododendrons get yellow in higher pH soils; they're iron hogs, among other ions that are more available in acidic conditions. That can be countered, I have a dark green rhodie at a pH of 6.5.

    Cold and wet ground conditions also impact the absorption of iron. Binding is fast and easy all the time, but wetter soils oxidize iron faster. Plus processing back to available iron is much slower in chilly temperatures.

    So foliar iron is particularly advantageous in fall (or early spring, but it's going to grow out fast as grass growth resumes).

    But over time, your goal should be to raise soil iron and conditions to the point that you don't need to spray much, if at all. I currently spray only once a year, and only for aesthetics.

  • danielj_2009
    9 years ago

    Interesting. So if I spray liquid iron onto the leaf in it's free ionic form (a salt), it will be used by the plant right away, but if it gets down into the soil it will likely bind up with something, then requiring bacteria to make it available to the plant.

  • danielj_2009
    9 years ago

    Interesting. So if I spray liquid iron onto the leaf in it's free ionic form (a salt), it will be used by the plant right away, but if it gets down into the soil it will likely bind up with something, then requiring bacteria to make it available to the plant.

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    Yep, iron sulfate is a salt, it dissolves relatively easily in water and the ions separate. The bond is polar.

    That's not to say that iron in soil solution won't be available for at least a short time--use of Milorganite proves that it is. But the more alkaline the environment, the shorter the availability.

    Chelated iron can be available at higher pH, but there are limits (no form is available well over a pH of 7.6). Iron humate tends to perform best, which what iron bound to organic matter turns into.

    For that reason, adding small amounts of iron to compost bins and piles isn't a bad idea. A small handful per cubic yard, great. More than that, no--it's too acidic.

    Which is another point. The final reactions on ferrous sulfate are acidic (small amounts of sulfuric acid are produced and the reaction is chemical, not biological, and happens in all soils). All told, iron sulfate is about one eighth as acidic as turned-in elemental sulfur by weight.

    Which makes it a reasonably good acidifier that can be applied at the soil surface, is pretty harmless to plants, and won't out-gas as sulfur dioxide (smog) like sulfur will at the surface.

    Four ounces per thousand is a negligible amount and doesn't need to be counterbalanced Even ten pounds per thousand can be counterbalanced by a very small amount of calcium carbonate.

  • forsheems
    9 years ago

    I stopped in Tractor Supply this morning and picked up a jug of CNI 6 Iron. According to the label it contains 15% Nitrogen (urea), 3.5% Sulfur, and 6% Chelated Iron. It was $30 for the 2.5 gallon jug. Mixed it up in the sprayer with a couple bottles of baby shampoo and applied it at 5 ounces per K. The directions say 4 to 6 ounces per K so I split the difference. Right now my lawn is very green but the color has definitely faded since my last Milo app in September. The rest of the neighborhoods crabgrass lawns are now brown too which makes mine look better. Guess we'll see what happens.

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    >>I stopped in Tractor Supply this morning and picked up a jug of CNI 6 Iron. According to the label it contains 15% Nitrogen (urea), 3.5% Sulfur, and 6% Chelated Iron. It was $30 for the 2.5 gallon jug. Mixed it up in the sprayer with a couple bottles of baby shampoo and applied it at 5 ounces per K.

    I started a trend. :-) What was the size of the jug?

    >>Guess we'll see what happens.

    If the color loss was incipient dormancy, not much. If it's just cooler, damper soils, it'll have a good effect if your lawn is yellowing.

    Either way, the iron will still be there in spring. It binds well.

  • forsheems
    9 years ago

    Morph, it was a 2.5 gallon jug. At 5oz per K application rate that works out to about $7 per app on my 14k front lawn. Not too bad and with everything else I have going on its worth a few extra bucks in the time it saved.

    At this point it's been down for 24 hours and there is a very noticeable improvement in color. Not that the color was bad, just wasn't as dark as I felt it could be. There was no yellowing at all, just a lighter shade of green than I wanted. According to the weatherman we're supposed to get 1/2" of rain by noon tomorrow. It's been 2 weeks since we've had rain so this should help out a little too.

    Last year I had a simple soil test done by the county ag extension that showed my pH is low (around 4.5) which is typical of the soil around here. I put down lime over the winter and plan to have the Logan test done soon to really take things to the next level. Just curious, when would be the best time to collect the soil samples for the test? Since late September I've done a milo app and two urea apps and still need to apply the winterizer urea app when the timing is right. How long should I wait after the winterizer to get the most accurate test?

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    Awesome! It's surprising that color is disappointing at a pH of 4.5, that's usually where iron availability is excellent. You could be really iron short in the soil, or something else is going on (nitrogen availability suffers at a pH that low, and that also impacts color). Not to mention magnesium availability, which is the central molecule of chlorophyll.

    You can take a soil test any time the soil isn't frozen, but at this point it's too late to do anything about any issues this year. Still, you could get the plan solidified for next year.

    The winterizer, which was primarily nitrogen, doesn't contain enough other elements to throw the test (and I ignore nitrogen reports anyway, and Logan doesn't test them). Nitrogen goes all over the place daily and even hourly.

    The Milo won't get in the way, nor will the urea. Urea's a flash in the pan, and the Milo will be semi-permanent in terms of the organic matter anyway.

    Testing right after heavy phosphorus or potassium additions isn't a good idea (they haven't had time to work in yet so the answer can be deceptive), but you haven't done that.

    You can lift, dry, and ship it off now if you want--and get a really fast answer as November isn't exactly Logan's heavy test period.

  • danielj_2009
    9 years ago

    Well I think I lucked out with the winterization. I got it down yesterday and then we've had rain ever since and temps in the 40's. Also, for the fun of it I put down some of that Bonide liquid iron. I could only find one spray bottle so I used that on the KBG. The odd thing is that the instructions said to apply until you see runoff, but if you do that you will empty the whole bottle in about 10 square feet! I had to move quickly to cover the recommended 5000 sf. I sprayed a patch of my neighbor's (brownish) lawn to see if the iron actually does anything in this cold weather.

    Thanks!

  • morpheuspa (6B/7A, E. PA)
    Original Author
    9 years ago

    Given the rain, you lucked out. And temperatures tumble tomorrow.

    Iron...on brown lawn, it probably won't do a thing. Although a little will get into the soil, by spring it'll be bound up and the change isn't that much.

  • mahtab93
    2 years ago

    Hi @morpheuspa (6B/7A, E. PA)

    I know this is an old post but, hoping you see it.


    Im thinking of using some ferrous sulfate this year on my tall fescue lawn (central NJ) and wanted to know if there is any restrictions on what temps it can be used in? Also, how frequently can you apply the iron sulfate with the nitrogen (ammonium sulfate, miracle gro, urea, etc)? I would think you would need to cut back in the summer or maybe just on the nitrogen to not over exhaust the grass during high stress season.

  • hoganjr
    2 years ago

    Unfortunately Morph doesn’t come around here anymore. Yeah you really should not spray iron if temps are near 85 degrees

  • mahtab93
    2 years ago

    Thanks @hoganjr .

    Sad to hear about Morphe.



  • danielj_2009
    2 years ago

    I believe he still frequents a site with initials ATY (figure it out). Not allowed to post links to other websites here, I think.