Frequently Asked Questions

What is Milorganite

Milorganite is composed of heat-dried microbes that have digested the organic material in wastewater. It's manufactured by the Milwaukee Metropolitan Sewerage District, which captures waste water from the metropolitan Milwaukee area and uses naturally occurring microbes to digest the nutrients. After the organic matter has been consumed, the cleaned water is returned to Lake Michigan and the resulting material is dried and marketed as Milorganite.

Is it poop in a bag?

No. It’s been a common misconception that Milorganite is “poop in a bag.” Milorganite is composed of microbes that have eaten well, died, and been dried. Microbes eat the organic material found in wastewater, die when they have nothing else to eat, and are heat-dried at temperatures up to 1200⁰F. Milorganite complies with all applicable federal and state requirements. It’s safe to use throughout your yard and garden when used as directed.

Where can I buy Milorganite?

Milorganite is available at most lawn and garden stores across the country. Our store locator can help you find a store near you. Retailers, landscape, and golf professionals can get Milorganite from our extensive distributor network, which is often the same supplier for other lawn and garden products they purchase.

What does 6-4-0 mean?

Every bag of fertilizer has an N-P-K nutrient analysis, which indicates the amount of nitrogen (N), phosphorus (P), and potassium (K) it contains by weight. Milorganite’s analysis is 6-4-0, which guarantees it contains at least 6% nitrogen, 4% phosphorus, and less than 1% potassium.

Why has Milorganite’s Iron guarantee changed from 4% to 2.5%?

The analysis of Milorganite has fluctuatednaturally 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 continueto have independent research conducted to ensure that any changes in nutrientvalues don’t negatively affect the outcomes homeowners have grown toexpect—healthy, long-lasting, green lawns. Learn more...

Why has Milorganite’s Phosphorus guarantee changed from 2% to 4%?

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.

Does the phosphorus in Milorganite contribute to runoff or leaching?

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.

How far from a waterway should I fertilize?

Do not fertilizer within 10 feet of any waterway, including oceans, lakes, rivers, streams, and ponds to help prevent phosphorus runoff.

When can I apply Milorganite?

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.

What if I apply too much Milorganite?

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 study 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.

Why does the Milorganite bag have a different application rate for FL, MD and MI?

Florida, Maryland, and Michigan 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 36 lbs. per 6,000 sq. ft. Check with your local cooperative extension agency to obtain specific information on local turf best management practices.

What is the setting for my spreader?

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.

Does Milorganite need to be watered in immediately after application?

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.

Can Milorganite be applied to my wet lawn?

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

Can Milorganite be applied in the summer or during drought?

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.

Does Milorganite kill weeds?

No. Milorganite is strictly a fertilizer. No herbicides are added to kill weeds or pesticides to kill bugs. It promotes a thick, healthy lawn, which helps choke out existing weeds and prevent weed seeds from germinating.

Does Milorganite contain grass seed?

No, Milorganite doesn’t contain grass seed. It can, however, make spreading grass seed easier and more accurate, especially for smaller seeds, such as bermuda grass. Mix four-parts Milorganite with one-part grass seed by weight. Decrease the amount of Milorganite applied during your normal fertilization schedule to avoid over-fertilization.

Can I use Milorganite in combination with other fertilizers, herbicides, or pesticides?

Yes, Milorganite can be used as part of your overall fertilization and lawn-care program in combination with other products, including fertilizers, herbicides, and pesticides. 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.

Can I apply a grub control at the same time as Milorganite?

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.

Can I apply Milorganite and lime at the same time?

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.

Can I use Milorganite in my vegetable garden?

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.

Does Milorganite help keep deer away?

Milorganite fertilizer makes no claims regarding its use as a deer repellent. For more information on research and testimonials.

Can I apply Milorganite on top of mulch?

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 from the bed or rake back the mulch a few inches from the base of plants, apply Milorganite, work it lightly into the soil, then return the mulch. This will immediately put Milorganite indirect contact with the soil.

What should I do if my dog at Milorganite?

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

When can my dog return to the lawn after I apply 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.

Is Milorganite effective in clay soil?

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.

Is Milorganite effective in sandy soil?

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.

What's the difference between fertilizers derived from organic versus synthetic sources?

Fertilizer derived from organic sources are composed of nutrients from living things or their byproducts, such as microbes, animal waste, plants, and other similar natural materials. It’s “slow food” for plants. Organically derived fertilizers feed plants slowly over a longer period of time and help build soil structure. Organically derived fertilizers contain no chemical salts,which can burn plants. Synthetic fertilizers are plants’“fast food,” as they are fast-acting once watered in. They’re manufactured using inorganic materials, chemicals, and the air, and have a high potential for burning plants, as well as leaching and runoff.

What is organic lawn care?

Organic lawn care works with nature rather than against it and can help build healthy soil, which can solve many lawn problems. An organic lawn care strategy reduces a number of things: pollution in the atmosphere; nutrient run-off into waterways; waste in landfills; and, inorganic chemicals in the soils that can disturb the natural order of life.

Is Milorganite approved for use on commercially grown USDA organic certified crops?

No, Milorganite isn't approved to be used on commercially grown USDA certified organic crops which are sold as “certified organic” produce.

Is Milorganite safe?

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.

Does Milorganite contain metals?

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.

Does Milorganite contain pharmaceuticals?

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.

Milorganite's Safety Data Sheet (SDS)

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).