When And How To Use Milorganite For The Best Results | The Ultimate Guide

If you want a thick, lush, green lawn, you must ensure that you provide it with all the necessary nutrition. And, to do that, you have to fertilize your grass. Fertilization is a way to ensure that your lawn receives a healthy supply of essential nutrients such as nitrogen, potassium, and phosphorus. Many excellent and noteworthy fertilizers are available on the market, but the one we will talk about today is Milwaukee’s Milorganite. Keep reading to learn about when to use milorganite.

when to use milorganite

Photo Credit Milorganite is an organic nitrogen-rich fertilizer explicitly designed to green up lawns.

Milorganite is an organic, slow-release nitrogen fertilizer that is the byproduct of a sewage treatment plant. It is composed of heat-killed microbes that have digested the organic matter from the wastewater. You can apply Milorganite to your lawn every 7 to 8 weeks during the active growth season of your grass. Its slow-release formula allows it to stay on the soil for longer, giving the grass nutrients slowly over time.

So, continue reading, and I will tell you everything there is to know about using Milorganite on lawns and making the best out of fantastic organic grass fertilizer.

RELATED: Milorganite Vs. Scotts | Which Is Best And Which Should You Use?

What Exactly Is Milorganite?

What Exactly Is Milorganite?

Photo Credit The slow-release formula of Milorganite cuts down mowing time, making it ideal for use anywhere, anytime.

Manufactured by the Milwaukee Metropolitan Sewerage District, Milorganite is an all-organic, slow-release, nitrogen-rich lawn and garden fertilizer. According to Milwaukee, it is among the oldest brands of fertilizers in the country that are available on the mare today.

And, believe it or not, Milorganite is made from the heat-killed bodies of microbes that have engorged themselves on organic materials in the sewage water.

The way this process works is the wastewater from the sewage is collected into large ponds. The water is then treated with microbes that feed on the organic matter present in the water. After the treatment with microbes is complete, clean water is released into Lake Michigan.

What is left behind is a slurry of microbes that have engorged themselves on the organic matter, which is then heat-dried at high temperatures to dry the product and kill the bacteria.

The leftover becomes Milorganite and is packed and shipped to gardening stores, fulfilling the fertilizer needs of millions of households around the country.

Is Milorganite Safe To Use?

If you are concerned about the safety of Milorganite, you are not alone. Many people often ask us, is Milorganite safe to use? After all, it is made from recycled wastewater and microbes. Many people even go as far as calling it “poop in the bag.”

So, should you be worried about using it? Well, the composition of Milorganite sounds a bit disgusting and slightly concerning. However, you should not be concerned about using it. Humans have been using wastewater for fertilization for a very long time.

And besides that, the meticulous process of producing Milorganite involves heating the product at extremely high temperatures of 800 to 1200 degrees Fahrenheit. In addition to drying up the product, the heat also kills and cleans the slurry o any bacteria.

How about the United States Environmental Protection Agency (US EPA) if you do not trust me? The meticulous manufacturing process strictly follows the guidelines of the US EPA. And the bacteria in the mix also undergo several tests to ensure they are safe.

In a nutshell, Milorganite is one of the safest organic fertilizers to use on lawns.

When To Apply Milorganite To Your Lawn?

When To Apply Milorganite To Your Lawn?

Photo Credit Both cool-season and warm-season types of grass should apply Milorganite around Labor Day.

According to the company’s official website that makes Milorganite, you should remember what they call “a holiday schedule” to apply Milorganite to your lawn, backyard, or garden. They suggest using the product every eight to ten weeks during the active growth season of your turfgrass. However, the specific holiday season for your grass will depend on whether you have southern (warm) season grass or northern (cool) season grass.

They also suggest mixing the grass seeds will Milorganite when overseeding a lawn to give the seedlings a head start in life. However, it would help if you combined the seeds and Milorganite in the proper ratio. For most yards, it is 1 part seeds and four parts Milorgaite.

Furthermore, when spreading Milorganite on your property, please use the right spreader setting and calibrate it for the granule size. You also do not necessarily need to water the lawn after using Milorganite. It stays on the ground until the moisture and temperature are ideal for the granules to break and release their nutrients in the soil.

However, if you want quick results, watering in Milorganite will improve the speed of fertilization by increasing the contact between the ground and granules and helping the granules break down. Nevertheless, let’s get to the main topic and discuss the best time to apply Milorganite on a lawn to make the best out of this product.

Applying Milorganite To New Lawns

Before we discuss how to fertilize established (cool-season and warm-season) lawns using Milorganite, let’s first discuss its use on new grass. When feeding a new yard with Milorganite, mix it in the top few inches of the soil before spreading the seeds.

Then, sow the grass seeds, and once the seedlings emerge and you have mowed your lawn at least two to three times, use two 32-pound Milorganite bags to fertilize your lawn. Although, it is two times the recommended rate for fertilizing established lawns with Milorganite. However, the extra nutrients will help the new grass set itself in the ground.

Following this, follow the suggested application rate and schedule (outlined below) for your grass region/type. However, I highly recommend that you follow the two-times recommended rate for the first year (64 pounds or two 32-pound bags/2,500 square feet).

Milorganite | New Lawn Application Rates
Sod / SeedRecommended Application Rate
Sodding64 pounds / 2,500 square feet
Seeding64 pounds / 2,500 square feet

Applying Milorganite To Warm-Season (Southern) Grasses

Applying Milorganite To Warm-Season (Southern) Grasses

Photo Credit Bermuda grass is a warm-season grass adapted to the warmer regions of the southeast United States.

If you reside in the southern areas of the United States, you probably have a warm-season turfgrass in your yard. Common examples of warm-season grasses include Bahira grass, Centipede grass, Zoysia grass, St. Augustine grass, and Bermuda grass.

These grasses need to be fertilized at least four times a year with Milorganite for the best results. However, if you have Centipede grass or Bahia grass on your lawn, you should fertilize them in the spring, and also, please do not fertilize these grasses in the fall to avoid winterkill. Also, avoid fertilizing warm-season grasses too late in the fall.

One way to tell for sure that it is time to fertilize your grass with Milogranite is the greening and growth of the lawn once the last frost has passed. However, please also note the soil and air temperatures. So, it would help if you fertilized the yard when soil temperatures are consistently in the 60s, and air temperatures are in the 70s.

If you fertilize too early, grass will use all available nutrients to grow its shoots, and the root growth will be affected. Fertilizing a bit late helps grass focus on root growth, which ensures that grass becomes drought resistant when the summer heat hits the ground.

You can use this tool to determine the soil temperatures for your region.

Lastly, avoid fertilizing warm-season grasses too late in the fall. You should be done with fertilizing your grass in the fall at least one month before the first frost. Fertilizing your grass late at this time makes it less cold-hardy as it goes into dormancy.

Nevertheless, here is Milorganite fertilizing schedule for warm-season grasses:

Milorganite | Warm-Season Grass Application Rates
When to ApplyApplication Rate
Easter (Once the grass has broken its dormancy)32 pounds / 2,500 square feet
Memorial Day (from 15th to May 31st)32 pounds / 2,500 square feet
Labor Day (from 1 to September 10)32 pounds / 2,500 square feet
Early October (from 1 to October 10)32 pounds / 2,500 square feet

* you can also apply Milorgamite when overseeding warm-season lawns.

RELATED: Ironite Vs Milorganite: What’s The Difference And Which Is Better?

Applying Milorganite To Cool-Season (Northern) Grasses

Applying Milorganite To Cool-Season (Northern) Grasses

Photo Credit Red Fescue is a cool-season grass used in the cooler, northern regions of the United States.

If you reside in the Northern areas of the United States, you probably have a cool-season turfgrass in your yard. Common examples of tall fescue grass, fine fescue grass, perennial ryegrass, annual ryegrass, rough bluegrass, and Kentucky bluegrass.

Like warm-season grasses, these also need to be fertilized four times a year with Milorganite for the best results. You can start fertilizing your grass when the last frost has passed, and your grass starts to green up. Once again, please ensure that soil and air temperatures are suitable for applying the Milorgnaite for the best possible results.

You can use this tool to determine the soil temperatures for your region. For cool-season grasses, you need to wait till the soil temperatures are consistently in the 50s, whereas the air temperatures are consistently in the 60s. Do not fertilize too early, or grass will use all of its nutrients on shoot growth which will make the lawn prone to heat stress.

As for the last Milorganite application in cool-season grasses, fertilize as late in the fall as possible. So, it would be best to fertilize before snowfall or the first deep freeze. It is known as dormant feeding, and it helps the grass grow more vigorously in the summer.

Nevertheless, here is Milorganite fertilizing schedule for cool-season grasses:

Milorganite | Cool-Season Grass Application Rates
When to ApplyApplication Rate
Memorial Day (from 15th to 31st May)32 pounds / 2,500 square feet
Canada Day (on July 4)32 pounds / 2,500 square feet
Labor Day (1st to 10th September)32 pounds / 2,500 square feet
Thanksgiving (near mid-November)32 pounds / 2,500 square feet

How Many Bags Of Milorganite Do I Need?

How Many Bags Of Milorganite Do I Need?

Photo Credit The recommended application rate for Milorganite is one 32-pound bag per 2500 square feet.

Here is a table that briefly summarizes the number of Milorganite 32-pound bags you need to fertilize properties, yards, and lawns of different sizes:

Yard SizeBags of Milorganite
2,500 square feetOne bag
1/4 acreFive bags
1/3 acreSix bags
1/2 acreNine bags
2/3 acre12 bags
3/4 acre13 bags
1 acre18 bags

It is important to remember here that if you have a one-acre property, it will have some concrete surfaces, such as a patio, walkway, and driveway in it. You will not need 18 full bags to fertilize it. So, the recommended bags here are just an estimate.

Can You Use Too Much Milorganite?

Can You Use Too Much Milorganite?

Photo Credit Too much Milorganite can damage your grass by promoting the development of weak roots.

Like any other lawn fertilizer, it is possible to overuse Milorganite. However, with Milorganite, the consequences of overapplying the product are nowhere near as damaging as overusing a synthetic fertilizer. However, the key is to be patient with the application.

If you think adding more Milorganite to your soil will green up your lawn faster, you could not be more wrong. Milorganite is a slow-release organic lawn fertilizer that releases its nutrients slowly over eight to ten weeks in the ground. So, if you are looking for a quick green-up of your grass, you should probably look for a synthetic fertilizing product.

Moreover, you might be surprised that applying too much nitrogen and iron to your lawn can damage the grass. When too much nitrogen or iron is present in the soil, the grass uses it for leaf or shoot growth instead of root growth.

Furthermore, excess nutrients in the soil can be easily washed away with rain or overwatering, which could end up in local water bodies. So, if you accidentally spill too much Milorganite on your lawn, I recommend taking a rake and picking it up.

However, there is no need to worry! Milorganite won’t burn your grass.

How Many Times Should You Apply Milorganite?

Ideally, you should fertilize your lawn with Milorganite at least four times a year. However, if you want to apply Milorganite only once, you should do it in the active growth season of your lawn grass. The vigorous growth season for cool-season grasses is fall and early spring. In contrast, it is late spring and early summer for warm-season grasses. 

How To Use Milorganite For Best Results?

How To Use Milorganite For Best Results?

Photo Credit Mix Milorganite into the top two inches of soil for best results before seeding or sodding.

Thankfully, the application process of Milorganite is not as meticulous as its manufacturing process. It is almost the same as any fertilizer. All you need is a few simple lawn/gardening tools, and you are good to go. These tools include but are not limited to

  • Aerator,
  • Lawn spreader
  • Milorganite

Application Process

Here is how to apply Milorganite to your lawn:

  • Water your lawn for at least two to three days before spreading Milorganite on your property. However, make sure the grass blades are dry when applying Milorganite.
  • Next, aerate the lawn soil. Aeration involves punching small holes in the ground, which helps the fertilizer reach and absorb in the grassroots better.
  • Once done, pour the Milorganite into your spreader and calibrate it for the granule size. Please ensure that you spread the product evenly all over your lawn.
  • After spreading the Milorganite granules, water the product. The moisture will help break down the granules faster and increase nutrient absorption.

RELATED: Lawn Fertilizer Schedule | When To Fertilize Your Grass For The Best Results?

Milorganite Vs. Scotts

Even though Milorganite works fantastically at greening up lawns and other turf areas, it is relatively slow in its action. And, sometimes, you might need a quick solution to your yellowing or dull yard, for example, for a short outdoor gathering or party.

A synthetic product such as Scotts Green Max Lawn Food can help in instances like this. However, it is a manufactured/synthetic product, and it has its advantages and disadvantages. For your comfort, here is a comparison of these two products.

Pros of ScottsPros Of Milorganite
Safe for use
Ensure fast results
It supplements the plants
Does not stain when directions are followed
Offers deep greening within some days
It ensures rapid growth
Suitable during any season
Easy to use
It is non-leaching
Reduce mowing and conserve water
Ensure deeper green color
It is an excellent repellent for wildlife
Safe for pets and childrenIt has met all quality standards of the EPA
It does not burn the plantsEasy to use

Final Thoughts

Milorganite is a fantastic, slow-release organic fertilizer that is safe to use and provides continuous nutrients to your grass. And, even though you can use it at any time of the year when your grass is actively growing, experts recommend using it during the peak growth period of your turfgrass to make the most out of your money and effort.

Frequently Asked Questions (FAQs)

How long does Milorganite take to work in the grass?

Milorganite takes about one week to effect, depending on the lawn conditions. The nutrients in Milorganite are released slowly over eight to ten weeks. And once the grass absorbs the nutrients, you will begin to see changes in the color and growth of your grass.

Can I Use Milorganite with other lawn fertilizers?

Milorganite can be used alongside your regular fertilization, lawn-care regimen, and other products, including pesticides, herbicides, fertilizers, and fungicides. However, please do not overfertilize your lawn; you might do more harm than good.

Can I mix Milorganite with Scotts?

In theory, you should be ok if you mix and apply Scotts with Milorganite. However, once again, be careful and do not overfertilize your grass. Both Scotts and Milorganite are nutrient-rich fertilizer products and should be mixed carefully.

Does Milorganite promote grass growth?

Milorganite is a fantastic general fertilizer that can promote healthy turfgrass growth. It improves the soil’s ability to grow grass and other plants. Furthermore, Milorganite is composed of 85% organic matter, which feeds healthy soil microbes and grass.

Can Milorganite burn grass?

Even in the hottest and driest temperatures, Milorganite will not burn your lawn because it contains almost no salts. However, an overabundance of Milorganite will weaken the roots of your grass, leaving it more vulnerable to drought and summer heat.

Sources for Further Reading

Using Milorganite to Repel White-Tailed Deer from Perennials. The University of Georgia. (2023). Retrieved February 11, 2023, from https://extension.uga.edu/publications/detail.html?number=C889-1

FS839: How to Calculate the Amount of Fertilizer Needed for Your Lawn (Rutgers NJAES). Rutgers | New Jersey Agricultural Experiment Station. (2023). Retrieved February 11, 2023, from https://njaes.rutgers.edu/FS839/

Benefits of using lawn fertilizers containing slow-release nitrogen. Diane Brown, Michigan State University Extension – May 23, 2014. (2014). Retrieved February 11, 2023, from https://www.canr.msu.edu/news/benefits_of_using_lawn_fertilizers_containing_slow_release_nitrogen

Now you know when to use milorganite. Also, check out our other articles:

Chelated Iron For Lawn? Is It Any Good, And How To Use It Correctly?

What Is The Best Height To Cut Your Grass For A Healthy Lawn?

How To Water Your Lawn For Best Results? & How Often Should You Do It?