Milorganite vs Ironite: What Are the Differences?

Last Updated on July 20, 2021 by Grow with Bovees

Milorganite is an organic lawn fertilizer high in iron, while Ironite is an iron supplement. Milorganite keeps your lawn healthy sustainably by releasing nutrients slowly. Ironite is a quick-releasing product that helps you get your lawn greener in a short time.

Does your lawn look yellow? It needs some iron. Both Ironite and Milorganite offer this nutrient and many people love both brands. But how do you know which one to use?

We compiled this handy guide so you know exactly what each one does and how you’ll get the biggest benefit from them.

  • What is Milorganite?
  • When to use Milorganite.
  • What is Ironite?
  • When to use Ironite.
  • Milorganite or Ironite which one to use?
  • Positives and negatives of Milorganite.
  • Positives and negatives of Ironite.
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Milorganite vs Ironite Comparison

If you want deep green grass, you’ll have to give your lawn some additional nutrition on top of just water. Maybe you’ve heard of Ironite and Milorganite, but you’re not sure about their differences.

To begin understanding the difference between Milorganite vs. Ironite, we first have to go through the basics. Let’s look into what each of these products contains.

What Is Milorganite?

Milorganite is an organic lawn fertilizer, which means it’s made from naturally recycled microbes. It includes nitrogen for growth, potassium for strength, and iron to keep your lawn greener, as well as other numerous micronutrients that maintain a healthy lawn.

Lawn fertilizers’ nutrient profiles are usually expressed as numbers referring to their NPK—nitrogen, phosphorus, potassium—macronutrient content. Milorganite’s formula is 6-0-4, which means it has at least 6 percent of nitrogen and 4 percent potassium, and less than 1 percent of phosphorus. On top of these nutrients, it has 4 percent iron.

When to Use Milorganite

If you have cool-season grass, such as fescue grass or bluegrass, you can use Milorganite four times a year. We recommend you use it when the grass gets green and is actively growing, and when temperatures are consistently above 6 degrees Fahrenheit.

For these types of grass, you can do your last application late in the year, around Thanksgiving. This will keep your lawn healthy through the winter when it’s dormant.

For warm-season grasses, aim for four applications a year, starting in the late spring when the temperature is over 70 degrees. Don’t do the last feeding in the fall later than Halloween, since this type of grass can suffer from late feeding. At least a month to six weeks before the first frost should be enough.

Positives and Negatives of Milorganite

Milorganite has a slow-release formula that keeps your lawn healthy for longer and doesn’t give all the micronutrients into the ground straight away after applying. It stays in your soil for up to 10 weeks, freeing the nitrogen and iron when your plants need it.

Thanks to its low salt content, Milorganite doesn’t burn your soil like synthetic fertilizers can do if you’ve applied a bit too much or in high heat. It also won’t stain concrete if it gets into contact with it.

On the negative side, Milorganite doesn’t give such a quick boost of growth and color as synthetic fertilizers or nutrient supplements will. If your goal is to just get the lawn looking dark green and healthy fast, Milorganite won’t be of much help.

What Is Ironite?

What many people don’t know is that Ironite is not a complete fertilizer. Instead, Ironite is a lawn supplement that you can apply on your lawn together with the fertilizer or on its own, whenever your lawn looks like it needs a little bit of help.

Ironite’s formula is 1-0-1, which means it’s much lower in nitrogen and potassium. Ironite is high in water-soluble iron, which helps your grass grow green fast.

When to Use Ironite

You can apply Ironite in addition to your regular fertilizer applications or when needed. We recommend using Ironite four times a year, together with your regular feeding schedule, and no more than 10 applications per year.

Positives and Negatives of Ironite

The good thing about Ironite is that it’ll make your grass greener and stronger without making it grow faster. Complete fertilizers usually include nitrogen, which gives you some extra work when mowing your lawn.

Ironite also works fast. Its synthetic formula can improve the appearance and feel of your lawn in a couple of weeks, without the need for much more water.

The negative of Ironite is that it’s easy to go overboard in the application, which can damage lawns and give them a grayish tone. Another possible issue with Ironite is that it easily stains everything it comes in contact with, from your concrete driveway to your fence.

Ironite is also marketed as safe for home use, but it has been flagged as a possible source of heavy metal leakage, specifically lead and arsenic.

Milorganite or Ironite Which One To Use?

Still not sure which is better, Ironite vs. Milorganite? Here are some extra tips so you know which one to pick in specific situations.

For A Greener Lawn

Ironite is your top choice if you want that thick, dark green lawn. While Milorganite is also high in iron, most people use Ironite as a great quick boost of strength for your grass.

For Improved Soil Quality

To improve your lawn, you need to take care of your soil, and the best way to go is with something that gives your lawn multiple micronutrients, like Milorganite. While a synthetic product like Ironite can provide a quick fix to give your plants a nutritional boost, you need a complete fertilizer for healthy soil in the long term.

For an Eco-Friendly Lawn Solution

If you want to pick the most eco-friendly product, always go for organic instead of synthetic lawn care products. When it comes to Milorganite vs Ironite, the first one is the right pick.

The slow-release formula of Milorganite doesn’t have as much runoff into waterways as Ironite, because it releases micronutrients steadily into the ground.

Organic fertilizers like Milorganite also work in a natural way, bringing natural nutrients back into the soil without charging it with synthetic chemicals. This is important for your soil, and your plants’ health, in the long run.

For a Shortage of Nutrients

Which way to go depends on what nutrients your yard needs. If your lawn is generally healthy but just lacks a bit of green and thickness in the blades, it may have an iron deficiency. In this case, we recommend Ironite, together with your normal fertilizer schedule.

If you’re not giving your lawn any fertilizer and you’ve noticed it grows slow and patchy, Milorganite is the right option. You need to feed lawns at the right time of year for them to be healthy eventually, so patience and a complete fertilizer are key.

If you’re not sure, do a soil test with a pH soil tester kit, to find out the pH and know what is lacking in your yard.

Final Thoughts on Ironite vs. Milorganite for Lawns

Making an absolute pick between Milorganite vs. Ironite is not simple, because both products are great for a home gardener.

Milorganite is a natural product and can help your lawn sustainably in the long run. Still, applying Ironite every now and then with your lawn feed product of choice is a good quick fix.

Just remember that the two products are not interchangeable. Milorganite is a fertilizer, while Ironite is a high-iron supplement. Both can be beneficial to keeping your lawn strong and green. If you want to play it safe in lawn care, do a soil test to be sure.

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