Milorganite vs Ironite – Differences + Which to Use on your Lawn

If you want a deep green grass, then you have to provide your lawn with some additional nutrients on top of your routine fertilizer and watering. You can easily achieve this through application of molorganite or ironite. Let’s look at the difference between the two, how they work and which to use on your lawn.

Milorganite is a slow-release organic fertilizer containing 2.5% iron and a 6-4-0 ratios of nitrogen, phosphorus and potassium. It helps your lawn grow greener, fuller and thicker. While Ironite is a quick release mineral supplement containing 20% iron and 1-0-1 NPK. It helps to green up a yellowing lawn within a few days of application.

What’s the Difference between Ironite & Milorganite?

Ironite is a mineral supplement rich in iron. Plants requires iron to create chlorophyll which a green pigment necessary for photosynthesis. Fertilizing your lawn with Ironite helps to make grass greener within a few days of application.

On the other hand, Milorganite is an organic fertilizer containing nitrogen, phosphorus and small quantities of iron and calcium. Milorganite fertilizer has no scorching effects. It improves the health of your lawn as well as quality of the soil.

Unlike Ironite that is used to treat iron deficiency, Milorganite is a slow-release fertilizer containing 6% Nitrogen, 4% Phosphorus and 2% Iron. These nutrients improves the health of your lawn by enhancing deep green color and strong root development.

The table below contain a summary on differences between Ironite and Milorganite:

It takes a few days to notice results after application.It takes a few weeks to notice results after applying on your lawn.
Ironite is a mineral supplement used as an additive to turn grass green.Milorganite is a slow-releasing nitrogen fertilizer applied to grass to grow fast, fuller, thicker and green up faster.
It has 20% iron content together with other micronutrients.Contains only 2.5 % iron content.
Contain salts that can burn the lawn when applied excessively especially when the weather is hot or when not watered in after application.Milorganite does not contain salts and cannot burn your lawn even when applied excessively.
Ironite contains 8% calcium.Milorganite contains 1.2% calcium.
Ironite is used to restore the green color when it begin to turn yellowish.It is applied on lawn to get a deep green color at a steady pace.
Ironite enriches the lawn with iron sulfate together with other nutrients that enhances greening.Milorganite provides the lawn with soluble nitrogen and small quantities of iron to boost growth and greening.
Fertilizing lawn with Ironite helps to boost the green color without causing excessive growth.Milorganite also helps to make grass greener while promoting thicker growth.
Ironite is a 1-0-1 fast-release iron supplement for grass.Milorganite is a slow release fertilizer containing nutrients like nitrogen and phosphorus.

Can I use Milorganite and Ironite?

You can use either Milorganite or Ironite on your lawn. However, it isn’t a good idea to mix both. Using both of them at the same time is a waste of nutrient. Excess iron can also pose a risk both to environment and plants. You do not want to risk burning your lawn or polluting the eco-system.

To choose the best product, it is recommended to conduct a soil test. It helps to determine the exact nutrient that is lacking in your soil in addition to proportions needed. For deficiency of iron, soil test suggest the product to use and the amount needed.

For other lawn specifications, you have to know your priorities, what is needed in garden, the cost and to choose what is better between Milorganite and Ironite. Several factors can guide you in making the right decision when selecting the right supplement. They include:

Result Time Frame

If you want deep green lawn within a few days, Ironite will do the trick. Liquid Ironite is easily absorbed by the plants to give results within a few days of application. On the other hand, Milorganite tend to take more time before releasing nutrients into the soil. Probably 3 to 4 weeks.

Soil Quality Improvement

If you are looking for a product to promote greener growth as well as improving health of the soil, then Milorganite more advantageous as compared to Ironite. Milorganite is 85% organic and does not contain harmful heavy metals like lead and arsenic that are present in Ironite.

Safety of the Product

Milorganite is safe to handle since it’s organic. On the other hand Ironite is made from harmful synthetic chemicals. Extra care should be take when applying it on your plants. Ensure to wear gloves, gumboots, and face mask when handling it.

Greener Lawn

Both Milorganite and Ironite contain iron that helps to turn yellowing lawn into a greener color. Milorganite contain other nutrients that help to make your lawn greener as well as improving the quality of the soil. While Ironite is specifically for greening up plants.

Cost of the Product

Cost is also considered when choosing the best product to use on your lawn. It’s a good idea to visit several shopping centers to compare the price tags. Generally, Milorganite is cheaper than Ironite. A 3 pound bag of Ironite retails at $5 while a 32 pounds of Milorganite goes for $15.

Which is better to use on lawns?

If your lawn is turning yellow, it needs some iron. Both Ironite and Milorganite contain iron. So, how do you know which one is better to use on lawn? First, you have to understand the content of each product and its efficiency. Let’s have a look at each of them.


Ironite is not a complete fertilizer. Instead, it is a mineral supplement containing iron and other micronutrients. Can be applied on your lawn alone or together with other fertilizers. Its formula is 1-0-1, this means that it has very little amount of nitrogen and potassium with zero phosphorus.

Ironite contain quick-release iron, it helps to turn your lawn into a deep green color within a few days of application. It dissolves in water easily so as to be absorbed by the grass almost instantly.

This mineral supplement is applied on lawn in addition to your regular fertilizer application. It is used to treat iron deficiency in the soil. It is recommended to apply Ironite on your lawn for at least four times a year. However do not exceed 10 applications per year. Like other supplements, Ironite has its pros and cons. Let’s have a look at them

Advantage of using Ironite on Lawn

Fertilizing your lawn with Ironite promotes stronger and greener grass without excessive growth. When we compare Ironite and nitrogen fertilizers, both of them helps to make grass greener. However, nitrogen fertilizers promotes faster growth that give you an extra work of mowing your lawn.

Ironite work fast to give positive results within a few days unlike to slow-release fertilizers that may take a couple of weeks to show results.

Disadvantages of using Ironite on lawn

Ironite has scorching effects. It may end up burning your lawn when applied excessively or during wrong weather condition. Hot weather conditions to be specific.

Many gardeners have also reported the issue of stain. Ironite is likely to stain anything that it comes in contact with such as fences and concrete pathways.

There is also high chances of going overboard in the application of Ironite. Earlier, we saw that excess application can lead to lawn burn out. If you are using liquid Ironite, it is recommended to mix it with a natural dye so as to demarcate the areas treated.


Milorganite is a slow-release organic fertilizer containing soluble nitrogen to boost growth, phosphorus for root development and iron to keep the lawn green. It also contains other micronutrients that are important to your lawn.

This fertilizer is ideal for both cool and warm season grass. For cool-season grass such as perennial ryegrass, fescue grass or Kentucky, you can apply Milorganite for at least 4 times a year. It is recommended to use this fertilizer when the grass is growing vigorously.

While for warm-season grass, apply this fertilizer late in spring when the temperatures are above 70 degree Fahrenheit. During this time, the grass is actively growing and requires sufficient nutrients to maintain the green color.

Advantages of using Milorganite Fertilizer on Lawn

Given that Milorganite is a slow-release fertilizer, it releases nitrogen, phosphorus and iron into the soil slowly for a longer period of time as required by the plants. It can last in the soil for up to 10 week.

Being organic fertilizer, it improves health of your lawn as well as that of the soil. It’s also environmentally friendly. Does not contain chemicals that may end up polluting underground water or streams.

Excessive application does not burn your grass, thanks to its low salt content. You do not want to have patches or discolorations of burnt grass in your garden.

Disadvantages of using Milorganite on Lawn

Milorganite is a slow-release fertilizer, it takes a couple of weeks to show some positive changes after application. If time is the essence, this is not the best supplement to choose when you want fast results. Its high nitrogen content also promotes faster growth that requires frequent mowing.

Final Thought

Milorganite and Ironite contains iron and other nutrients that promotes greener growth. However, Ironite helps the lawn to green up without growing faster and thicker. On the other hand, Milorganite enhances green color as well as fuller and thicker growth.

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