How to Apply and Use Milorganite® in Your Lawn

By Jaime Staufenbeil - Milorganite Agronomist
May 19, 2022

What is Milorganite?

Milorganite is a naturally derived, slow-release nitrogen fertilizer. It’s derived from the wastewater treatment process in Milwaukee, Wisconsin. Microbes eat the organic matter and when they’ve had their fill, the remaining material is processed, kiln-dried, and bagged as Milorganite.

The NPK analysis of Milorganite is 6-4-0. That means there’s 6% nitrogen (N), 4% phosphorus (P), and less than one percent potassium in each bag. Milorganite also contains 2.5% non-staining iron, which customers rely on for the greenest lawns possible. Here’s information on how each nutrient supports plant health. Milorganite also contains a number of micronutrients plants need in very small amounts, but because there is less than 1% of each in Milorganite, they can’t be listed on the bag.

For additional information on Milorganite, check out the video What is Milorganite? by horticulturist and gardening expert, Melinda Myers.

Using Milorganite in Your Lawn

When soil temperature and moisture levels are right, Milorganite is broken down by the thriving ecosystem in your soil and nutrients will feed your lawn for up to 8-10 weeks.  Its nutrients are slowly released, which means nutrients are available to grass at a rate it can use, which also reduces the risk of runoff. Milorganite contains 2.5% non-staining iron, which will make your grass as green as it can be without rust stains on your walks and driveway. Milorganite also adds organic matter to the soil, which helps to condition the soil and retain moisture.

When to Apply Milorganite to the Lawn

Milorganite’s “Holiday Schedule” will help you remember when it’s time to fertilize your lawn.

  • Milorganite schedule for Northern, cool-season grasses:
    • Memorial Day (mid- to late-May)
    • July 4th (mid-summer)
    • Labor Day (early-September)
    • Thanksgiving (mid-November AFTER lawn is dormant and BEFORE first frost)
Milorganite | Cool-Season Grass Application Rates
When to Apply Application Rate
Memorial Day, mid to end of May 32 lbs per 2,500 sq ft
July 4th, Canada Day 32 lbs per 2,500 sq ft
Labor Day, early September 32 lbs per 2,500 sq ft
Thanksgiving, mid November 32 lbs per 2,500 sq ft
Milorganite | Warm-Season Grass Application Rates
When to Apply Application Rate
Easter (after turf breaks dormancy) 32 lbs per 2,500 sq ft
Memorial Day, mid to end of May 32 lbs per 2,500 sq ft
Labor Day, early September 32 lbs per 2,500 sq ft
Early October (or when overseeding)* 32 lbs per 2,500 sq ft

How Much Milorganite to Use on the Lawn

  • The rate of Milorganite to use on an established lawn is 32 lbs. (one bag) of Milorganite for every 2,500 sq ft.
  • Some states limit the amount of fertilizer that can be used, as well as the percentage of slow-release nitrogen the fertilizer must contain. Florida and Maryland, for example, limit the application rate to 32 lbs. of Milorganite for every 5,200 sq ft. Always check state and local fertilizer ordinances and restrictions.

How to Apply Milorganite to the Lawn

Always use a drop or broadcast spreader to evenly distribute Milorganite to your lawn, making sure to overlap rows during application.

Tips for Applying Milorganite to the Lawn:

  • Mow your lawn before fertilizing with Milorganite to help increase soil contact. 
  • Apply half of the recommended amount of Milorganite going in one direction, then apply the other half in the opposite direction. This helps to ensure an even application.
  • Milorganite provides a list of some of the most popular spreaders and settings to use for applying Milorganite. If you don’t find your spreader listed, we recommend using these easy instructions to calibrate your spreader. You’ll only have to do it once.
  • Your speed can change application rates. Walk at a steady pace while fertilizing. Walking faster distributes less Milorganite while walking slower distributes more.
  • Milorganite doesn’t need to be watered in like synthetically made fertilizers, although watering or rain will speed up the process of releasing nutrients into your lawn.
  • If you can only fertilize once a year, fall is the best time.