Nitrogen vs. Iron for Lawns

Are you looking for ways to make your lawn greener and are wondering whether to use nitrogen or iron? While they serve the same purpose, they are meant to be used in different applications as explained in this article.

A full and lusciously green lawn is every home or lawn owner’s dream. There are, however, specific periods where you may notice open patches on your lawn or yellow sections on the grass. When this happens, it is almost always an indication of iron or nitrogen deficiency. They are both credited for keeping lawns green, full, and luscious, but they are applied at different times for different reasons. This article breaks down the uses of nitrogen and iron in lawns, how to identify their deficiencies, and when to apply them to the said lawn. Here goes.

What are the differences between Nitrogen and Iron?





Making lawn full, promoting green color in grass

Development of chlorophyll, balancing soil pH




Application times

Cooler seasons (fall)

Any time

Signs of deficiency

Yellowing of older and lower grass blades, patches on lawn

Yellow or bleached spots on grass blades


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Nitrogen vs. Iron for Lawns – How do they compare?

Product Type

Even though they are essentially used for promoting grass health in near similar ways, these two compounds are not of the same type. Nitrogen is a compound found in fertilizer and is rarely presented on its own. This is why it falls under the fertilizer category. It is added as a nutrient supplement in the soil to promote certain physiological functions in the grass during different stages of its growth and development. As a fertilizer, nitrogen has a direct impact on the plant itself, but none on the soil into which it is added.

Iron, on the other hand, is presented as an additive. While most soil additives are meant to improve the physical, chemical, and biological structure of the soil alone, iron is introduced so that it can have a direct impact on both the soil and the plant itself. The reason why it is not categorized as a fertilizer, therefore, is that it has an impact on the soil, especially because it works to balance pH in the same. Unlike fertilizer which is mostly added routinely, iron is used on a need-to basis, especially when you spot a deficiency in your grass lawn.

Even though these two compounds do not fall under the same category, iron makes the better one of the two since it has a direct impact on both the soil and the plant while nitrogen only targets the plants.

Product Uses

As mentioned, nitrogen is used as a fertilizer which is routinely added to the soil to improve the growth, development, and maintenance of grass lawns. This compound is considered one of the most vital for plants since it facilitates the formation of specific proteins which are essential for the growth of plant cells. In essence, plants, including lawn grass, cannot survive without the presence of nitrogen in the soil. This is one of the reasons why it is applied routinely to make sure that your soils are constantly replenished. Nitrogen is, for this reason, used as an essential nutrient source for plants right from seed planting to plant maturity.

Comparably, iron is used as a nutritional supplement for plants. What this means is that, while it is helpful, it is not particularly as essential, and you do not have to use it to get a healthy grass lawn. Iron is introduced into the soil for two main reasons; to act as a chlorophyll builder in the grass blades, and to help balance soil pH. Your grass lawn can, however, make its own chlorophyll without particularly needing the help of added iron, and this is why it is not considered essential. In addition, there are many other compounds used to balance soil pH, making iron an alternative rather than an essential.

Since plants cannot germinate, grow, develop, and survive without the presence of nitrogen, it makes a better compound than iron which is not a mandatory requirement for lawns.

Application times

Since nitrogen is an essential fertilizer, it should be used as part of your annual lawn maintenance program. Most nitrogen is made into slow-release fertilizer, meaning that it can be used up to 4 times in your lawn depending on its needs and the general climate of your region. If you live in the cooler northern regions and have a cool season grass, you can use this schedule; apply at the end of May, beginning of July, early September, and mid-November. If you are in warmer regions and have warm-season grass, apply nitrogen in early to mid-April, end of May, early September, and early October.

Being that iron is a supplement, it can be used during any time or season of the year. This is largely because it is used on a need-to basis, giving you the freedom to determine when it is best to apply it. However, in certain regions, you may notice that grass becomes iron deficient in early spring. You can use it in the spring, as long as your lawn shows signs of iron deficiency.

Because iron can be added at any time of the year, it makes a better compound than nitrogen which must be scheduled based on different seasons and lawn needs.

Signs of deficiency

When a grass lawn does not have as much nitrogen as it needs to flourish, you are going to notice a characteristic yellow color on the blades of grass, especially the lower and older ones. You may also, depending on the severity of the deficiency, notice missing patches of grass where the growth of grass is adversely affected. Other signs include patches of drying grass as well as the presence of weeds in certain areas throughout the lawn.

When a grass lawn is iron deficient, one of the first things you are going to notice is a lighter shade of green on the leaves. Unlike the uniform yellow unique to nitrogen deficiency, the one seen in iron deficient lawns presents in patches on the grass blades. In most instances, the tips of the blades may be a much lighter shade of green than the rest of the blades, and when the deficiency is bad, the edges may become yellow.

Nitrogen deficiency is worse for grass lawns because it has more and harsher effects on the grass when compared to iron deficiency.

Nitrogen vs. Iron – Comparison Overview

Nitrogen Overview

Nitrogen makes an integral part of lawn growth and health, and this is why it is considered a vital element in the soil. It is obtained from three main sources; natural, inorganic, and synthetic production. Natural nitrogen is obtained from such compounds as manure, grass clippings, and animal by-products while synthetic nitrogen is obtained from such compounds as urea, polymer-coated urea, urea triazine, and others. Inorganic nitrogen is achieved from nitrates of ammonium, calcium, and potassium, as well as ammonium sulfate.

Nitrogen fertilizers are mostly categorized into two; slow-release and quick-release fertilizers. Slow-release nitrogen fertilizer is released over the course of several weeks. Some of its advantages include; a lower risk of fertilizer burn to the lawn, reducing dense growth, feeding the lawn for longer, and being more economical. Fast-release fertilizer leaches into the soil much faster, causing more rapid growth and curing deficiency faster.


  • Excellent for plant growth and development
  • Enhances the green color of the grass
  • Keeps weeds and dryness away
  • Provides essential nutrition


  • Too much of it can cause the grass to burn

Iron Overview

Even though it is not considered a must-have by most lawn owners, iron is an important additive to grass lawns because it directly affects the grass and the soil. One of the things that stand out most about iron is that its effects are seen only a couple of days after application. It is a fast-acting compound that works to correct the deficiency and reverse the effects of the same when added to the soil.

Apart from enhancing the beauty and health of your grass lawn, iron also helps in the maintenance of proper soil pH, and also allows lawns to use less water. Additionally, iron makes nutrients a lot more available to plants, and it contains calcium which helps grass and other vegetation resist diseases.

Unlike nitrogen fertilizer, iron does not require a specific application schedule and can be used whenever it is needed. Caution should be taken, however, not to add too much into the soil.


  • Promotes development of chlorophyll
  • Reduces the amount of water used in lawns
  • Helps to balance soil pH
  • Makes nutrients more available to plants


  • Too much makes the grass turn grey.

Verdict: So, which one is better; Nitrogen or Iron?

Seeing as they are both used to solve different problems, none is placed above the other. If you are looking to enhance lawn growth and improve the color of your grass, nitrogen is the way to go. If, however, you are dealing with glass blade chlorosis and poor soil pH, iron is the better option of the two.


How many types of iron are available?

There are two main types of iron; liquid iron and granular iron.

Can I add nitrogen fertilizer to potted plants?

Yes, you can. You must, however, use a very concise amount to prevent burning your plant with an excess of the same.

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