Should You Apply Milorganite Every Month?

A highly trusted and well-established brand of fertilizer, Milorganite is composed of heat-dried microbes (chock full of organic matter from digested wastewater) that use a slow-release formula to continue adding nutrients to the soil long after the initial application.

The result is that you do not have to apply it every month to reap the benefits because that is not how the product was designed. Read on to find how often you should actually apply Milorganite, and to determine the right fertilization schedule according to your location and type of grass.

What Happens if You Apply Milorganite Too Often?

The great thing about Milorganite is that it continues releasing nitrogen and other nutrients into the soil for up to 8-10 weeks after its first application, which promotes even growth and deeper root development.

But ten weeks is a long time to wait if you are eager to prolong and enhance the results, and it can be tempting to keep adding fertilizer.

Definitely resist this temptation because, rather than enhancing the results of Milorganite, too much fertilizer will render them useless and damage your lawn.

This is because much nitrogen can “burn” your grass and turn it into a yellow-brown eyesore. In the end, you will give yourself a ton of unnecessary work to do, as you try to fix your mistakes and figure out how to make your lawn look green again.

Other negative side effects of over-fertilization are poor root growth, which will weaken the grass and decrease its tolerance to overly hot or cold weather, and excessive blade growth, which will lead to a buildup of thatch that sucks the moisture from the grass and can increase the likelihood of fungal diseases.

The Correct Application Schedule for Milorganite

The correct application schedule depends on the type of grass you are fertilizing and your location. Cool-season grasses tend to grow in the north while warm-season grasses tend to grow in the south.

For cool-season, northern grasses, (Kentucky Bluegrass, Fescue, Perennial Ryegrass) the first fertilizer application should take place from mid to late May, after the last frost, and when the grass is growing in green again.

One way to think of it is as fertilizing your grass on “the holiday schedule”, with the first application taking place on Memorial Day.

Continuing in that vein, you should wait until Canada day or July 4th to apply Milorganite again.

Labor Day, or early September, is when you should apply Milorganite for the third time. Mid-November, or American Thanksgiving, is the last time you will feed your lawn until spring when the schedule begins again.

The only caveat is that, if you live in a cold area with early winters, you might want to consider fertilizing your grass for the last time at an earlier date than mid-November, as the point is to wait until as late into the season as possible, before the last frost or the first snowfall. Because your grass is going into dormancy, the longer you wait the more vibrant it will be when it “wakes up” in the spring.

For Southern, Warm-Season Grasses (Bermuda, St. Augustine, Zoysia, *Centipede Grass, *Bahia) the first application should take place on Easter, or early to mid-April because this is when the grass breaks out of winter dormancy.

Schedule the second application for Memorial Day, or mid to late May, and the third application for Labor Day, or early September.

The last application should take place in early October. And, if you live in an area with killing frosts, fertilize your grass less than one month before the average date of the first killing frost.

*Centipede Grass and Bahia prefer spring and summer feedings but don’t like fall feedings. Fertilizing them in the fall can cause winterkill.

If the lawn you are fertilizing is brand new, and there is no grass yet, you should mix Milorganite into the upper two inches of soil before adding seeds to the grass or laying sod. After you have mowed the lawn a third time, you can start fertilizing the grass with thirty pounds of Milorganite per square foot, which is the amount of fertilizer recommended any time you are using Milorganite.

How Often Should You Apply Milorganite?

Overall, though there are certain grasses that you can fertilize less than four times a year, you should never apply Milorganite more than four times a year.

Follow the above schedule for the best results and, obviously, wait at least ten weeks between applications.

How Long Does It Take for Milorganite to Show Results?

If it takes 8-10 weeks for Milorgonate to finish spreading through the soil, does that mean you will have to wait that long to see the results?

The short answer is no. Milorganite should take effect within the first few days and the grass should appear greener. After two weeks, you should notice a major difference.

The slightly longer answer is that, in order for the microbes to take effect, Milorganite needs to be applied in the proper conditions.

The soil temperature should be between 55- and 80-degrees Fahrenheit (14 to 27 degrees Celsius) and, before applying, you should mow your grass a bit lower than you usually would. Do not apply fertilizer if you know there is going to be heavy rainfall, or it will wash away.


There is no reason, no matter how tempting, to apply Milorganite to your grass every month. You risk weakening your grass, burning it with nitrogen, or choking it with excess growth.

Rather, you should allow the Milorganite to take the two months it needs to fully replenish your soil, and rest easy knowing you’ll see results within the first few days.

Fertilize your grass four times a year, in the spring, summer, and fall, and apply thirty-two pounds of fertilizer per 2,500 square feet. No doubt your lawn will reward you with luscious growth, as Milorganite is an old and reliable brand of fertilizer, known for its consistent and clear results.

Also read

Should You Apply Milorganite Before Rain?

Best Milorganite Alternatives for Your Lawn

Milorganite vs Ironite – Difference and Comparison

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