Ironite Vs Milorganite

Both Ironite and Milorganite are excellent nutrient supplement that helps lawn grass grow and color. It’s time to use Ironite or Milorganite if your grass isn’t growing thick and turning a rich green hue. What’s the difference between the two, though?

Milorganite is an organic fertilizer with 2.5 percent iron and 6-4-0 NPK, whereas Ironite is a lawn supplement with 20 percent iron and 1-0-1 NPK. Ironite is a quick-release mineral that makes grass greener. Milorganite is a slow-release fertilizer that helps lawns grow faster and thicker.

A healthy lawn has a deep green tint to it. While there are several ways to do so, water, sunlight, and manure may not always be sufficient. To achieve a greener-looking lawn, you can use Milorganite or Ironite, but Milorganite is better for your lawns.

Ironite and Milorganite

In our guide, you can learn much more about Ironite vs. Milorganite and which one can give you the best healthy lawn. (Read Is 15-15-15 Fertilizer Good For Lawns)

By the end, you’ll have enough information to decide between Milorganite organic fertilizer to give you a lush green lawn, or will an Ironite comparison lead you in that direction?

Which Is Better Ironite or Milorganite?

Both Ironite and Milorganite are natural fertilizers, but their composition and action–or what they do to lawns–differ. Ironite supplement helps the grass turn green and healthy again when it discolor to turn yellow.

Milorganite is a nitrogen fertilizer that feeds your lawn for up to 10 weeks, allowing it to develop and green up more quickly. In addition, Milorganite is an organic fertilizer that will not burn your grass, even if you over-fertilize it.

Ironite and Milorganite vary in that Ironite helps the lawn turn green without excessive growth. Still, Milorganite helps your lawn’s health by promoting rapid growth and making grass thicker and fuller while delivering a deep green color.

The Milwaukee Metropolitan Sewerage District produces Milorganite, an all-natural brand-name fertilizer.

It is often asked, does Milorganite kill weeds? It doesn’t kill weeds, but it offers improved soil quality from the natural fertilizer.

Is Ironite and Milorganite The Same?

Here you can see the differences between Ironite vs. Milorganite


  • Ironite is a nutrient supplement to treat iron deficiency.
  • Contains 20% iron and other micronutrients.
  • The lawn supplement is a 1-0-1 additive.
  • Use when the grass begins to turn yellow.
  • The lawn supplements results are visible in a few days.
  • Can burn the lawn if applied excessively, during hot weather, or watered into the lawn soil after application.
  • You can get granular Ironite or liquid Ironite


  • Milorganite is a more eco-friendly fertilizer.
  • Contains 2.5% iron content.
  • It makes up a 6-4-0 organic slow-release nitrogen fertilizer.
  • Milorganite is an organic fertilizer used to strengthen roots in a grass lawn.
  • You get a deep green color from your grass at a steady pace.
  • It takes a few weeks for the organic lawn fertilizer to deliver results.
  • Milorganite feeds the lawn with soluble nitrogen and other micronutrients.
  • Because it contains no salts, milorganite does not burn grass when used in excess or at high temperatures.

Can I Mix Ironite and Milorganite Together?

Milorganite can be used as part of your yearly lawn management program because it is nitrogen fertilizer. However, applying it around four times per year is recommended because it is a slow-release fertilizer. (Read Zoysia Grass Fertilizer 16-4-8 Guide)

If you have cool-season grass like Fescue, Kentucky bluegrass, or Perennial Ryegrass and live in the northeastern United States, Midwest, or Pacific Northwest, use Milorganite at the following times:

  • Late May: 32 pounds per 2,500 square feet.
  • July 4th: 32 pounds per 2,500 square feet
  • Labor day: 32 pounds per 2,500 square feet
  • Mid-November: 32 pounds per 2,500 square feet

For warm-season grasses grown in the south, you can use this Milorganite fertilizer schedule:

  • Easter: 32 pounds per 2,500 square feet.
  • Late May around Memorial Day: 32 pounds per 2,500 square feet.
  • Labor day: 32 pounds per 2,500 square feet.
  • Early October: 32 pounds per 2,500 square feet.

Milorganite Application

  1. Before you plant your seed, mix Milorganite into the top couple of inches of your topsoil.
  2. Apply two bags of 32-pound Milorganite for every 2,500 feet of grass after your seedlings have grown and you’ve mowed your lawn three times.
  3. For the first year, keep doing this to improve lawn condition.
  4. Then, for every 2,500 feet of grass, apply one 32-pound bag of the lawn products.

Should I mix Ironite and Milorganite?

Using Ironite and Milorganite together is not a smart idea since too much iron is not only a waste of nutrients, but it also poses a risk of run-off into waterways and driveways, causing discoloration on concrete patios and drives.

Manufacturers of Milorganite advise against using varied iron supplements on your lawn like other nutrients, including iron. These can only be used in limited amounts by lawns.

As a result, toggle Ironite vs. Milorganite and using them together does nothing for healthy grass growth.

When Should You Apply Ironite?

Besides water, you’ll need to provide additional nourishment to your lawn if you want it to be deep green. You’ve probably heard of Ironite and Milorganite but aren’t sure what the differences are.

To understand the differences between Milorganite and Ironite, we must first understand the fundamentals of what your lawn requires. (Read About 19-19-19 Fertilizer For Lawns)


What Is Milorganite?

Milorganite is an organic lawn fertilizer, meaning it’s manufactured from bacteria that have been naturally recycled. It is a good fertilizer, which contains nitrogen for growth, potassium for strength, iron to keep your grass greener, and various other micronutrients that help keep your lawn healthy.

The NPK—nitrogen, phosphorus, potassium—macronutrient content of lawn fertilizers is commonly stated as a series of numbers.

Milorganite has a formula of 6-0-4, which means it contains at least 6% nitrogen, 4% potassium, and fewer than 1% phosphorus. It also contains a 4% iron supplement to boost iron deficiencies on top of these minerals to effectively re-green your lawn.

When to Use Milorganite

Milorganite can be used four times a year on cool-season grass like fescue grass or bluegrass. When you have a lawn green in color and actively growing, and the temperature is consistently above 6 degrees Fahrenheit, it is recommended for use.

You can apply your last treatment late in the year, around Thanksgiving, for these varieties of grass. This will maintain your lawn care and healthy soil and grass in the dormant winter season.

Aim for four treatments per year for warm-season grasses, beginning in late spring when temperatures are above 70 degrees.

This variety of green grass suffers from late feeding, so don’t do the last feeding for your lawn care in the fall or later than Halloween.

Pros and cons of Milorganite

Milorganite organic fertilizers contain a slow-release mix that keeps your lawn healthy for longer by not immediately releasing all the micronutrients into the ground. Instead, it can last up to ten weeks in your soil, releasing nitrogen and iron to maintain grass health.

Milorganite is great for lawn care as it doesn’t burn your soil like synthetic fertilizers can if you apply too much or under extreme heat.

Milorganite does not provide the same rapid increase in green lawn growth and colors as applying Ironite or nutrient supplements. Therefore, Milorganite won’t help you if you only want your lawn to quickly seem dark green and healthy.

Last, if you look at Milorganite vs. Iron, if you see the Ironite before and after, you will see the iron supplement stain concrete because of too much iron where Milorganite doesn’t.


What Is Ironite?

Ironite is not a complete fertilizer and doesn’t offer enough nitrogen or other macronutrients that many people are unaware of.

Instead, Ironite is a lawn supplement that you can use with fertilizer or on its own whenever your grass appears to need a boost to an iron deficiency.

Ironite has a 1-0-1 formula, which is poor in nitrogen and potassium. Ironite is abundant in water-soluble iron, which aids in the rapid growth in the Milorganite vs. Ironite race for grass growth.

When to Use Ironite

You can apply Ironite liquid form or granular Ironite along with your regular fertilizer applications or as required when needed to keep your grass green. Recommendations are to use Ironite four times per year and your regular feeding schedule and not go over ten applications per year.

Too much could affect soil quality, and to be sure you are not overdoing it, it is worth doing a soil test before and after the application of liquid Ironite.

Pros and Cons of Ironite

Ironite has the advantage of making your grass greener and more substantial without making it grow faster. Unfortunately, nitrogen is frequently included in complete fertilizers, which means you’ll have to do some extra work when mowing your lawn.

Ironite is likewise a quick-acting material. Its synthetic mix can improve the look and feel of your grass in just a few weeks, yet it doesn’t require much additional water.

Ironite has the drawback of being easy to overuse, which can injure lawns and give them a grayish tone. Another disadvantage of Ironite is that it stains everything it comes into contact with, including your concrete driveway and fence.

Ironite is also touted as safe for domestic use, although it has been linked to heavy metal leaks, including lead and arsenic.

With all the above in the Milorganite vs. Ironite comparison, you can go either way based on the requirements of your lawn.

For a healthy lawn, do a soil test to check if you have a deficiency. Better Ironite if you do, but if you don’t, go with Milorganite for long-term healthy grass.

Ironite Vs Milorganite (2)

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