Milorganite®: Frequently Asked Questions

We recommend applying Milorganite to your lawn four times annually for best results, although it can be applied any time during the growing season. Please see our lawn application page for rates and a schedule for your region of the country. We also have recommended application rates and schedule for flowers, vegetables, fruits, shrubs & trees.

It now takes less Milorganite to achieve the recommended nutrient application rates. The 32 lb bag of Milorganite will cover 2500 sq ft, just like the 36 lb bag did. Rather than require customers to re-calibrate their spreaders, we felt it was more convenient to reduce the bag size to achieve the same results. We always recommend calibrating your spreader to reduce the risk of over application and possible nutrient runoff.

Spreader settings for the most widely used spreaders on the market are printed on the Milorganite bag and available on our website. Unfortunately, it’s not feasible to test every spreader. We’ve provided spreader calibration instructions to help you determine the proper setting if you’re spreader isn’t listed.

The same nutrients you get from the original Milorganite (32 lb bag) is also available in a 50 lb Professional bag. The Milorganite Professional 50 lb bag is our Greens Grade product which is smaller granules. For the proper application, you will need to adjust your spreader settings.

Milorganite's salt-free formula won't burn your lawn, however, your lawn can only take up so many nutrients. Milorganite's application rates and schedule are based on university research, which studied the amount and frequency of nutrients needed for a healthy lawn. We caution that over fertilization can result in nutrient runoff into waterways resulting in serious environmental issues. For a healthy lawn, we recommend following good lawn care practices such as the recommend fertilization schedule and rates, proper mowing, aerating, and overseeding.

No, it's not necessary to water in Milorganite after application, which is one of its great features. It stays on the soil until water and temperature conditions are just right for soil microbes to break down the nutrients in Milorganite for plants to use. Although not necessary, watering in Milorganite will ensure the fertilizer is in contact with the soil and speeds up the fertilization process.

Mow first and then apply Milorganite to the lawn, so the Milorganite granule falls to the soil and has a shorter grass blade to fall through.

If you are not bagging your grass clippings, you can mow at any time. Recycle your grass clippings on the lawn. They do not cause thatch but will break down quickly adding moisture, nutrients, and organic matter to your soil.

Ideally, mow after watering your lawn or rainfall, so the Milorganite granules fall to the soil surface and are less likely to get picked up when you mow or bag your clippings.

Never dispose of fertilizer in waterways and keep all fertilizer away from waterways. Comply with any state laws for the minimum distance (typically 10-25 feet) between fertilizer applications and waterways to help prevent phosphorus runoff. Follow the recommended fertilizer application rates to help keep fertilizer from entering any bodies of water and not fertilizing before a heavy rainfall. After fertilizing, sweep excess fertilizer from solid surfaces, such as driveways, decks, patios, streets, and sidewalks, back into the lawn.

We do not recommend applying an iron supplement after applying Milorganite. Your Milorganite application contains a minimum of 2.5% iron which helps green your lawn along with nitrogen. Your lawn can only take up so many nutrients. Excess nutrients can result in nutrient runoff into our waterways, wasted money, product, and time. Over-fertilization can also stress out the turf plant and cause disease issues. Check out this blog article to learn more about what nutrients help make your grass green and what color green to expect from your grass type.

When you use Milorganite with other fertilizers we caution to not over-apply nitrogen fertilizer. Check the label of the product you applied for timing instructions. Typically, after 4-6 weeks you can put down an application of Milorganite. Milorganite doesn't contain salts so it will not burn your lawn, however, your lawn can only take up so many nutrients. Over-fertilization can result in nutrient runoff into our waterways, wasted money, product, and time. Over-fertilization can also stress out the turf plant and cause disease issues.

Yes, Milorganite can be used as part of your overall fertilization and lawn-care program in combination with other products, including fertilizers, herbicides, pesticides, and fungicides. Make sure to read the label of the other product to ensure there aren’t any restrictions and it’s safe for your lawn to use it in conjunction with Milorganite. Look for phrases such as, “not to be used in combination with…” When using Milorganite along with other fertilizers that contain nitrogen, make sure you don’t apply too much nitrogen.

Yes, Milorganite doesn't contain salts, so it can be applied to a wet lawn. It won't burn your lawn.

Yes, Milorganite can be applied at any time. It contains no salts, which makes it safe to apply during the summer and in drought conditions when used as directed. Fertilizer salts are responsible for burning lawns and plants. The nutrients in Milorganite will be released when there’s enough water and the temperature is right. This makes it an ideal fertilizer for water-restricted areas.

Grub control can be applied at the same as Milorganite, but if you do, we don’t recommend using a grub control product that contains fertilizer, as you may over fertilize your lawn. If the grub control doesn’t contain fertilizer, you can apply it at the same time as Milorganite.

Yes, Milorganite can be applied at the same time as lime as there is no interaction between the two. Lime should only be applied if a soil test indicates that it’s needed to change the pH of the soil to be either more acidic or alkaline. An optimum pH of 6.0 or 7.0 helps bring soil into balance and allows for optimum nutrient uptake by plants.

Yes, Milorganite is an excellent, and safe fertilizer for all outdoor plants, including vegetables when used as directed. It's slow-release nitrogen feeds plants evenly and gradually without excess nitrogen interfering with flowering and fruit development. This nurtures the roots, which in turn develop more robust yields. Other fertilizers may force rapid growth, which can result in skinny plants and reduced yields.

Yes, Milorganite can be applied on top of mulch, but it’s going to take a while for it to work its way into the soil. An alternative is to remove the mulch or rake back the mulch a few inches from the base of the plants, apply Milorganite, work it lightly into the soil, then return the mulch. This will immediately put Milorganite into indirect contact with the soil and speed up the process of feeding the plant.

Milorganite works well in clay soils, because it contains 85% organic matter by weight. The organic matter improves soil drainage and aeration, moderates soil temperature, and provides pore space in the dense clay, all essential for optimum plant growth.

There are several benefits that make Milorganite an ideal fertilizer to use in sandy soil, which generally doesn’t contain much organic matter or nutrients. Milorganite, which is 85% organic matter by weight, helps add organic matter to the soil. This helps to more effectively retain nutrients.The water-soluble nutrients are released slowly, reducing the chance of leaching. Adding organic matter also promotes beneficial microbial activity for healthy soil.

Florida, Maryland, Michigan, and Pennsylvania have restrictions as to how much phosphorus can be applied during the growing season each year. To comply with state regulations, FL, MD and MI residents are advised to only apply Milorganite two times per year at the rate of 32 lbs. per 5,200 sq. ft. Always check your local county ordinances for fertilizer application restrictions and blackout dates. Your local cooperative extension agency is an excellent resource to assist with specific information on local turf best management practices.

Milorganite is available at most lawn and garden stores across the nation. Our store locator can help find stores near you, or visit the Milorganite storefront on Amazon.

Retailers, landscapers, and golf professionals can order Milorganite through our extensive distributor network, which often serves as the same supplier for other lawn and garden products you purchase. 

We appreciate your support of Milorganite!

We do not sell direct, but work with a distribution network nationwide that supplies your local retailers. Our best advice to find Milorganite in your area, is to call or check your local retailer’s websites for available bags before making the trip to the store. Please visit our store locator for additional stores in your area.

Milorganite distributes a limited supply of bulk product through our distributor network. Homeowners, please work with your local retailer to assist with ordering Milorganite or visit our store locator.

Milorganite complies with federal and state standards for the protection of public health and the environment. Milorganite can be used with confidence for all of your fertilizing needs, including lawns, trees, shrubs, flowers, and vegetables when used as directed. For more information visit our safety page.

Milorganite meets all federal and state requirements and is registered for sale in all 50 states. For additional information, please see Milorganite's Safety Data Sheet (SDS).

The phosphorus in Milorganite is slow-moving and stays in the soil ready for plants to use. University testing has demonstrated that the phosphorus in Milorganite is less likely to leach or move into groundwater.

All fertilizers, organic and synthetic, contain some metals, including Milorganite. Metals such as lead, cadmium, copper, and zinc naturally occur in the environment. Several metals are actually needed by plants in small amounts - micronutrients - to grow and reproduce properly. We test Milorganite daily and confirm the average level of metals meets (or is less than) the EPA limits. Milorganite complies with federal and state standards for the protection of public health and the environment.

Milorganite is monitored regularly for a host of compounds to help ensure consumer safety. Milorganite, like manures and organic fertilizers, contains trace concentrations of pharmaceutical compounds, as well as household and personal care products. However, the very low concentration of these compounds makes potential risks negligible. Chemical and biological processes in the soil degrade these compounds, additionally reducing an already negligible risk. We encourage everyone to dispose of pharmaceuticals safely, not in sinks or down toilets, which can negatively impact waterways.

Per- and polyfluoroalkyl substances or “PFAS” are a group of more than 9,000 man-made chemicals that are fire, oil, grease, water, and stain resistant and are found in a wide array of consumer and industrial products, including non-stick cookware, food packaging, dental floss, cleaning products, and cosmetics.  

The makers of Milorganite, the Milwaukee Metropolitan Sewerage District, do not use PFAS in the production. Wastewater reclamation facilities are passive recipients of PFAS in wastewater from residential, commercial, and industrial products. PFAS concentrations in wastewater streams vary significantly depending on local industry and historical firefighting operations at local airports.

Milorganite strongly believes that control of PFAS sources before entry into the wastewater stream is the solution to continued PFAS contamination. 

National and state PFAS regulatory standards for biosolid fertilizers like Milorganite are still forthcoming. Several states have established Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) concentrations of less than 20 parts per billion (ppb) for biosolids like Milorganite.

Using EPA’s approved testing protocol for PFOA and PFOS, the 2025 results for these chemicals in Milorganite^® products average 3.1 ppb. 

By contrast, PFAS has been detected at much higher concentrations in various common products. You can view the chart on our safety page.

• Dust in an average home has 523 ppb  

• Lipstick contains 216 ppb to 1,560 ppb 

• Fast-food packaging is 7,000 to 876,000 ppb 

We recognize and share the public’s concern about PFAS and fully support more research into their impacts on public health. For more information, view the U.S. Environmental Protection Agency (EPA) website and PFAS fact sheet. 

First off, there’s no need to panic if your dog happens to eat Milorganite either off your lawn, garden or even directly out of the bag. It isn’t life-threatening or an emergency situation. Your dog may experience discomfort and outcomes you would expect when a dog eats something they shouldn’t. We recommend contacting your veterinarian for advice. We have a few pet safety tips to help deter your dog’s urge to taste-test Milorganite.

Some dogs are attracted to the odor of Milorganite, which may lead to them rolling on freshly fertilized areas or eating it off the lawn or garden. After spreading Milorganite, monitor your dog to determine their interest in Milorganite. If they show interest, keep them off your lawn for about 24 hours. You can reduce attraction by watering your lawn after application.

Milorganite is in short supply again this year —even with greater efficiencies to produce more. We’re not happy about it either. Customer demand is outpacing production and Milorganite can’t be produced using a supply-and-demand model. Our “natural resources” are limited. Learn more about our efforts.

We apologize for any inconvenience and appreciate your support of Milorganite. Please visit our store locator for additional stores in your area.

As a means of increasing awareness to over fertilization and the climbing nutrient values of our product, we’ve taken the responsible step of reducing our package size. The 32 lb bag of Milorganite now provides the exact same coverage as the former 36-pound bag—2,500 square feet of lawn. Spreader settings, coverage and effectiveness have not changed.

While Milorganite is one of the most environmentally friendly fertilizer products available, there is a fair amount of scrutiny in use of all fertilizers. We believe this change will help consumers and the environment. Learn more..

Milorganite’s source of nitrogen has remained unchanged since 1926. It comes from heat-dried pellets of once-living organisms. The definition of “organic” has been refined and we can no longer use the term to describe the nitrogen in Milorganite. We now only refer to it as “slow-release” nitrogen. Despite this change in terminology, Milorganite continues to provide the same benefits to homeowner’s lawns, landscapes, and gardens as it has for more than nine decades.

Milorganite is the result of a wastewater treatment process and the amount of nutrients, which are in the form of organic materials, naturally fluctuates. Over an extended period of time, we found that there was a consistent increase in the amount of nitrogen. When we demonstrated that the nitrogen (N) was consistently 6 percent, the analysis of Milorganite was changed from 5 to 6 percent.

The analysis of Milorganite has fluctuated naturally throughout its 90-year history, but its benefits to lawns, landscapes, and gardens has remained the same. Based on the changing dynamics of our processes, the iron content in Milorganite has been adjusted from 4% to 2.5%. We continue to have independent research conducted to ensure that any changes in nutrient values don’t negatively affect the outcomes homeowners have grown to expect—healthy, long-lasting, green lawns. Learn more...

Throughout Milorganite’s 90-year history, its nutrient analysis has fluctuated, but the benefits to plants have been consistent. Based on the changing dynamics of our processes, we’ve adjusted our phosphorus analysis from 2% to 4%. The phosphorus in Milorganite is readily available to plants, which supports root growth and tissue development, and continues to be less likely to leach compared to other fertilizers containing phosphorus. You’ll continue to get quality results with each application.