Can You Have Too Much Iron in Lawn – How To Fix It

Last Updated on January 26, 2022 by Grow with Bovees

Is your once gorgeous lush green grass turning brown, and you are not sure why? You might want to consider that your grass is getting too much iron.

A high concentration of iron can harm your lawn, causing it to go brown or gray-like due to a mild grass burn.

Most of the fertilizers used for winter, in fact, contain increased amounts of iron, and it should therefore never be used on a grass lawn that is unhealthy and one should always follow the instructions for use found on the product label.

Iron is great to use when you want to get rid of weeds and moss on your grass, as it is highly toxic to them without being a toxic chemical.


Ironite is a common iron supplement that can be used on your grass. In the human body, this mineral is found in hemoglobin which makes up part of its blood cells. It is packed with loads of nutrients and minerals, which can be quite beneficial to your lawn and its health if used correctly.

Does Iron Keep Your Grass Green?

Lawn professionals consider iron to be the secret weapon of keeping a lush green lawn. It is often used on golf courses to maintain the beautiful blue-green color of the grass without having to force it to grow with nitrogen fertilizer.

Lawn grass needs several valuable nutrients for optimal growth. Even the slightest of nutrient deficiencies can negatively affect your grass turf. Iron is an important micro – nutrient.

It is, in fact, a necessary micronutrient required for the proper growth of grass.

Type of Turf

Iron supplements are great to use on fescue and bluegrass, helping to keep the grass a beautiful dark green color throughout the hot summer months.

The Benefits of Iron on Your Lawn

Before we go through the negative effects of applying too much iron to your grass, let us look at how it may benefit your lawn.

Pests & Diseases

During the colder months of autumn and winter, your lawn becomes more prone to catching diseases.

If you make use of a decent liquid iron supplement during this time when your grass is more susceptible, you would aid in making it more resistant to disease, keeping it healthy throughout winter.

Iron also increases the acidity of your lawns’ soil. The high acidity may aid in the reduction of pesky worms which are often found squirming around in the soil underneath the grass lawn.

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Colder Climates

In some parts of the world, winters can become quite cold. These cold climates can have damaging effects on your grass lawn.

Treating your lawn with iron, makes it more hardy, helping it to survive when being exposed to a colder air temperature.

Moss & Weeds

As mentioned above, if your grass has a problem with excessive weed or moss growth, using high concentrations of iron is an effective way to get rid of them without making use of toxic chemicals.

Iron is toxic to weeds and moss, and if applied to them, they die, turn black and this makes them easier for you to remove.

Iron is the active ingredient in products such as Moss Out.

Effects of Too Much Iron on Lawn

Another frequently asked question is: Will an overload of iron kill grass or does it burn grass?

If you accidentally or unknowingly apply too much iron to your lawn, you will cause it to burn the grass blades, causing problematic black-green discoloration of lawn grasses. This often happens when using too much fertilizer.

Severe darkening of a grass blade is the most common sign.

The Importance of the Weather

As a rule of thumb, remember not to use iron in hot climates where temperatures are between 26-27 degrees Celsius and above. This heat will cause the grass to burn faster. Also, do not use it in too wet conditions as the iron may be washed away before taking effect on the grass.

Excessive iron will prevent your grass from growing healthy.

Treating Grass Lawn With Too Much Iron

First of all, check your fertilizer’s iron levels before continuing to use it and then reduce or adjust the amount and frequency of applying the fertilizer according to the iron concentration present.

Soil pH

Too much iron on grass results in a high soil pH, which can be damaging to the grass blades. Test your soils’ pH and if it is too acidic, try to reduce it. You can make the soil more alkaline by simply adding a bit of lime to your lawn.

Using Lime Products

There are a few different products of lime available for purchase. We suggest that you choose one which is best for you.

Lime also has other benefits, apart from making your grass’ soil more alkaline. It also adds nutrients such as calcium and magnesium to the soil, which is beneficial to the healthy growth of your lawn.

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Be careful not to add too much lime. Soil that is highly alkaline can be detrimental to your grass lawn. In order to reverse a pH that is too high, simply add some elemental sulfur.

Frequency of Iron Application to Your Lawn

If you are treating a domestic lawn, depending on where in the world you live, applying industry iron to it about four times per year — once every season — should be sufficient.

Always make sure that your lawn is not bone dry but also not overly wet when applying the iron.

For the iron to have a better effect on your grass lawn, apply it together with your regular fertilizer.

If you feel that your lawn is severely lacking in iron, you can apply it up to ten times per year.

Always wear clothes that are protective of your skin when applying ironite. These should include gloves, long sleeves and long pants. If you, by accident, expose your skin to ironite, thoroughly wash it with water after exposure.

When Is the Right Time To Add Iron to Your Lawn?

The application of iron when the weather and environmental conditions are optimal is crucial for the best result. If the weather is too hot with extreme temperatures, you could end up burning your grass and if it is too wet, you risk it from being flushed away.

Gardening experts advise to only add iron to your lawn during the winter months when moisture levels are not too high and the sun is not too bright.

Keeping the above information in mind, compare them to the weather conditions that are normal in your location, and add iron when it suits your climate or when you deem necessary.

Types of Iron Fertilizers

When going to the local nursery or gardening store, you will find that there are several types of iron fertilizer available for purchase. In order to make an informed decision when buying this fertilizer, we feel that you should know the difference between them.

Continue on for more information about a few iron fertilizers.

Iron Sulphate 

Ferrous sulfate is a very common type of iron fertiliser which is quite popular due to its affordability. Its concentration is about 20 percent iron and is most effective in lawns that have a pH of lower than seven.

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Chelated Iron

Water soluble chelated-iron products are compounds that work by stabilizing metal ions present in your lawn and protecting it from oxidation and rainfall. This compound is a mixture of many components. It includes sodium, ammonia, amino acids, citrate and Fe+3. It turns your turf green, but this green may last only a few weeks.


This is another form of iron fertilizer. This one, however, only works on lawns that are alkaline. It starts to become ineffective if the pH drops below 6.5.

Iron Deficiency in Lawns

Much like your lawn having too much iron, it can also become deficient in it. The most effective way to determine whether your lawn has an iron deficiency, is to send a few soil samples for testing. A soil test will provide you with an absolute answer regarding the iron level and levels of minerals in your soil.

How Much Iron?

If your lawn is lacking iron, remember that the average lawn would need roughly 0.7 ounces of iron for every 1000 square feet.


If your lawn has a severe iron deficiency, you will find that any freshly grown blades of grass have a pale yellow color rather than that lovely deep green that it is supposed to have. This is a common symptom of iron deficiency in lawns.


A lack of iron is often seen in grass lawn that are not properly established yet. This is commonly seen in household lawn, and it might be due to the soil’s unbalanced pH levels or due to there being too much sand mixed into the soil.

If it rains a lot or the lawn is excessively watered, this problem can also arise due to vital nutrients being washed away before absorption by the grass can take place.


I think it is safe to say that adding iron to your lawn is of great benefit, giving it a boost in growth and keeping it healthy, as long as you do not overdo it, in which case you may end up burning your grass.

The safest way to avoid having too much iron in a lawn is to figure out the frequency you wish or need to apply it and then continue by carefully following the instructions of the iron supplement you wish to use. This way, your lawn should be safe from turning brown.