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Iron for Lawns: Tips for Greener, Healthier Grass

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Written By: Mark Marino

a Massachusetts Core Applicator License holder and owner/operator of Lawn Phix,

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Do you ever pass a neighbor’s dark green grass and wonder how they get such a lush, green lawn? If your lawn remains a pale green verging on yellow, it might be suffering from an iron deficiency. Lawn grasses benefit from a lawn fertilizer with iron, but in order to determine if a liquid iron supplement is right for your lawn, you’ll need a soil test . If your lawn has a soil deficiency and you want greener grass, you can take steps to remedy the problem, which we’ll outline here.

What Does Iron Do for Grass?

Iron (Fe) for lawns is needed to support chlorophyll production and reduce moss growth. Chlorophyll is what gives lawns their deep green color. The greener the grass, the more chlorophyll your lawn is producing. Pale green grass growing in your yard suggests that your lawn grasses aren’t making enough chlorophyll to produce that vibrant green grass you want to see growing in your landscape.

If your lawn is actually a yellowish-green, it could be suffering from a condition called iron chlorosis, which is a severe iron deficiency. The fact is, healthy grass is not iron deficient. Lawn fertilizer may not always correct the problem either. If your lawn has acidic soil, it may struggle to absorb the iron that’s present in the soil. Be careful to determine your soil’s needs before you introduce a new active ingredient to it.

When to Apply Iron to Lawns

Although you can apply an iron supplement to your lawn any time, spring iron supplement applications are best. If you apply iron to your lawn in hot weather, it may not produce good results for your yard. Generally, spring is the ideal time to apply iron to your lawn when temperatures range between 40 and 80 degrees Fahrenheit. For this reason, winter may not be the right time to apply iron supplements either. However, summer application is usually to be avoided.

Types of Iron Supplements for Lawns

Iron for lawns comes in various forms. If your lawn lacks iron, you can rely on liquid iron supplements or other forms that we’ll discuss here. Adding iron can produce greener grass and a healthier lawn.

Liquid Iron

Liquid iron supplements for lawns tend to be the most popular. With proper application or iron, your liquid iron supplement can support fast chlorophyll synthesis, turning your lawn green quite quickly. Liquid iron sprays can be tricky to use as they can get everywhere–even on weeds, so be careful to use these iron supplements or fertilizers as directed for best results. The best liquid iron product is Blade Iron 15-0-0 – it works quickly to green up your grass and the one I use professionally throughout the season for my customers.

Chelated Iron

Chelated iron is a liquid iron fertilizer (that often comes with other nutrients) that helps to amend iron-deficient soil. Chelated iron is a great option because it prevents the iron in your soil from turning to rust and causing rust stains on your grass, which can happen with exposure to water and air. While small amounts of rust won’t hurt your lawn, a buildup can produce toxic effects over time. 

Granular Iron

If your grass and plants have an iron deficiency, you can add granular iron to your lawn can also correct the problem and enhance their growth. Granular iron supplements are easy to apply, but it’s also easy to miss spots. If you’re looking for a fast solution, liquid iron might be a better option for your grass. Granular iron takes somewhat longer to achieve those deep green results you’re looking for. Applying iron in spring is likely to achieve the best results.

More Iron for Lawns FAQs

Will iron green up my lawn?

If your grass is suffering from an iron deficiency, you can use an organic iron fertilizer or synthetic iron fertilizers to stimulate chlorophyll production (and reduce moss) in order to achieve a deep green lawn. On the other hand, iron deficiency isn’t the only cause of yellow or pale green grass growth. Acidic soil rather than low iron could be causing your lawn to have problems absorbing iron. That’s why it’s important to conduct a soil test before applying a liquid iron supplement or other iron supplements for best results.

How often can you apply iron to your lawn?

You should apply iron to your lawn in accordance with your iron supplement product’s instructions. While many property owners only spray liquid iron once per year, in spring or the end of winter, for example, others–especially turf managers of golf courses–may apply iron more often depending on the nutrient needs of their grass.

Although you can apply iron more often than once per year, take care not to overdo it with iron supplements in your lawn or garden or you could throw off the pH balance of your soil. Adding iron in excess can leave your grass looking a winter gray rather than a vibrant green.

What is the best iron for grass?

Many homeowners prefer water-soluble chelated iron fertilizer for their garden and lawn because it does not cause rust. However, you might spend less money on a liquid iron fertilizer and still get excellent results. Rust is unlikely to be a problem so long as you don’t overdo it with your iron supplements or organic iron sources.

Remember to test your soil before you add iron. Other soil factors may lead to problems for various grasses, including yellowing. Also avoid spraying your iron supplement on other garden plants, which might not need the nutrient.

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Author's Note: this piece has been updated for accuracy since its first publication on
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Author: Mark Marino
My name is Mark Marino, and I am the founder, owner, and operator of Lawn Phix. With a passion for lawn care and turf nutrition for over a decade, I've dedicated countless hours to correcting soil and perfecting lawns. Today, my expertise, backed by formal courses at UMass Extension Pesticide Education, allows me to offer top-tier lawn care services and advice. I am a fully licensed and insured lawn care applicator in Massachusetts, specializing in comprehensive turf nutrition, weed control, and lawn pest control. My license number is AL-0053865. Contact me at [email protected] or +1 (508) 500-8402.

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