When and How to Use Milorganite on Your Lawn for Best Results

If you’re a lawn owner with the hopes of having a perfect picture-like lawn, you cannot run away from this one activity that I’ll be showing you in a short while.

But before then, what does a perfect picturesque lawn look like?

A perfect lawn in the eyes of many gardeners is a lush green, full lawn, free of pests and diseases – the kind of lawn that’ll make you the envy of the neighborhood and maybe even have neighbors visiting you from time to time to know your secret.

This lawn condition has to be worked for, and no, I don’t mean you cannot get a perfect lawn if you don’t sweat daily working on your lawn. I mean, you need a conscious effort to improve the condition of your lawn.

With that being said, I promised to tell you the one activity you cannot run away from if you want to achieve a beautiful lawn. You cannot run away from fertilization.

Fertilization is very important as it continuously feeds the grass, keeping them healthy, fighting off pests and diseases while choking out any weed.

Now, the process of constantly applying regular N-P-K fertilizers may become tiring to many. That is why this particular product has jumped to the forefront of lawn owners’ fertilization needs.

This product is milorganite.

What is Milorganite, and Why Should You Care?

What is Milorganite

Milorganite is an organic nitrogen-based fertilizer made from wastewater. This wastewater is treated with microbes that ingest the nutrients in the wastewater. When the lake water is pumped to Lake Michigan, what is left is nutrient-rich microbes. These microbes are heat-dried to form milorganite. Milwaukee Metropolitan Sewerage District manufactures it.

Why should you even care about all these?

This simple process produces rich nitrogen-based fertilizers that your lawn needs. These organic microbes will slowly but continuously feed your lawn.

Is Milorganite Safe?

There are many concerns from potential users about milorganite since it is made from wastewater, with many people asking if it is ‘poop in a bag.’ 

No, milorganite is not poop in a bag and is completely safe to use. But don’t take my word for it; the microbes die after feeding on the wastewater and are then heat-dried under a temperature of 900 to 1200 degrees Fahrenheit. This temperature kills any dangerous pathogen that may have been left behind. The microbes also undergo numerous testing to ensure they are safe.

Are you wondering if milorganite carries a ‘poop odor?’ it does not have a poop odor but an earthly odor that quickly dissipates when rain or irrigation water falls on it.

When to Use Milorganite for Best Results?

When to Apply Milorganite

As with any fertilizer out there, timing is essential. Applying milorganite at the right time will mean faster and more efficient results.

When is the right time?

For effective growth, you need to apply milorganite between 3-4 times a year. Scheduling it right based on your type of grass is the key to milorganite success.

Not to worry, though, I’ve put together a quick guide to help you.

Apply Milorganite for Warm-Season Grasses

These are typical grasses grown in the South, and they include St. Augustine, centipede, and Bermuda grasses.

If you have warm-season grass and would like to get the best out of it through milorganite, the best time to apply milorganite for the year is between mid to end of March. Apply just when your grass begins to grow in spring and is green – Ideally, when the temperature has settled around the 70 degrees mark.

The next time you apply this milorganite is mid to end of May when the grass is still vigorously growing. At this point, it needs a lot of nutrients to supplement its vigorous growth.

The third and fourth time you should fertilize your lawn with milorganite is early September and early October, respectively. You want to avoid applying milorganite close to the fall as the fall is when the grass is preparing to go dormant.

Apply Milorganite for Cool-Season Grasses

These are grass you’ll most likely find in the North. They include Kentucky bluegrass, creeping bentgrass, and annual and perennial ryegrass.

how to use Milorganite for plants

It is recommended you apply milorganite 4 times a year to feed your lawn, keeping it green and healthy continuously.

Apply milorganite after the last frost when the grass starts to grow and when the daytime temperature is consistent around the 60 degrees mark around mid to early May. This is the best time to apply the first dose. This will encourage the plant to grow its roots properly and not just focus on its shoot.

The second schedule should be around early July, when the grass is still growing vigorously. Time the third application to fall around early September, while the last application should be left as late as possible into the season, ideally around the middle of November just before the deep freeze. 

While the application of milorganite close to the fall is discouraged for warm-season grasses, it is paramount for cool-season grasses to get fertilizer before the heavy freeze begins. This helps the lawn grow healthier in spring. 

It is advised to time your application to fall into the holidays of the year. This makes it easier to track and provides you with ample time to apply milorganite.

How to Apply Milorganite for Plants and Grass?

Thankfully the application process is not as deep as its manufacturing process. It is almost the same with any fertilizer.

How to Apply Milorganite

Before we talk about how you can apply this fertilizer, here are the tools you need.

Tools and Material Needed

  • Milorganite
  • Aerator


  • Water: You want to water the soil 2 -3 days before application to keep the ground soft but leave enough time for the grass blades to dry. Watering before application also helps the aeration process.
  • Aeration: Aeration is important as it will create holes that the milorganite can fall in. This not only helps the fertilizer reach the base quickly but also helps to loosen compact soil.
  • Pour milorganite in spreader: Place your spreader on a hard surface and pour your milorganite in the hopper. Make sure the hopper vents are closed to avoid some falling on the driveway.
  • Spread the milorganite: take the spreader to the far end of the lawn, open the vents and walk briskly across the lawn, forming a strip as you go. Do this till you have covered the lawn.
  • Water again: this time around, the aim is not to soften the ground but to wash off the milorganite from the grass’s blades and help in their breakdown and release into the ground.

How Long Does Milorganite Take to Work on a Lawn?

Milorganite is a slow-releasing fertilizer and takes between 1 and 2 weeks to start showing its effects. You’ll begin to see changes in the color and growth of your grass.

ironite vs milorganite

You may be wondering what the difference is between milorganite and ironite or if they are the same. Well, they are different products.

ironite vs milorganite

While milorganite is an organic fertilizer, ironite is a nutrient-based supplement. Milorganite helps the growth and encourages green color since it contains iron. At the same time, ironite is focused on improving the color of your lawn. 

Another big difference is the speed of their effect. While milorganite is slow-releasing, ironite is fast-releasing, and you’ll begin to see changes in the color of your lawn in a few days.

They, however, have some similarities in usage. They are both used on lawns.


Milorganite is an essential organic fertilizer that is not only safe to use but vital in providing continuous nutrients to your lawn.

It is advised to use a milorganite 4 times a year and schedule your application based on your type of grass.

About Jennifer Igra

Growing up in Brooklyn, New York City known for it’s green gardens. Jennifer, a 30 year old gardener and green living fanatic started Igra World to share her gardening journey and increase gardening awareness among masses. Follow Igra World to improve your gardening skills.

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