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What Is Milorganite Fertilizer Made Of?

UF/IFAS Gardening Solutions

Milorganite is made from heat-dried microbes (bacteria) that clean Milwaukee's wastewater. The microbes consume organic matter in the water, are then collected and kiln-dried at high temperatures to kill pathogens. The result is a 6-4-0 organic fertilizer with 2.5% iron. It's been produced since 1926 and is one of the oldest recycled-nutrient fertilizers in the world. It is NOT raw sewage, it's processed microbial biomass.

What You Need to Know

Milorganite is made from heat-dried microbes (bacteria) that clean Milwaukee's wastewater. The microbes consume organic matter in the water, are then collected and kiln-dried at high temperatures to kill pathogens. The result is a 6-4-0 organic fertilizer with 2.5% iron

It's been produced since 1926 and is one of the oldest recycled-nutrient fertilizers in the world. It is NOT raw sewage, it's processed microbial biomass.

For personalized recommendations based on your specific garden size and fertilizer, use our fertilizer calculator.

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