Gardening — Milorganite
Milorganite is a fertilizer made in Milwaukee from treated sewage sludge. It is categorized as a
natural fertilizer because 85 percent of its ingredients are organic, although the U.S. Department
of Agriculture does not allow its use in certified organic agricultural production. It is not compost.
The name 'Milorganite' is derived from the first syllable of these three words: Milwaukee, organic and
nitrogen.
Both Milorganite and chemical fertilizers are designed to nourish your grass. Because grass is
the largest plant in your yard, and the one that receives the largest abuse from weather, insects,
drought and mold, it requires a great deal of maintenance. It also needs feeding more frequently.
Unlike chemical fertilizers, it releases nutrients slowly, so it may be a better choice for preventing
excess nutrients draining into waterways and groundwater.
Unlike chemical fertilizers, it releases nutrients slowly, so it may be a better choice for preventing
excess nutrients draining into waterways and groundwater. Also, it's easy to over-fertilize with
chemical fertilizers which can result in 'burned' grass. Since Milorganite is an organic fertilizer
that contains low amounts of nitrogen it won't burn your grass, even if over-applied.
Fertilizer composition is listed in ratios of NPK -- nitrogen, phosphorus and potassium.
Milorganite contains 5 percent nitrogen, 2 percent phosphorus and .32 percent
potassium. It also contains the secondary nutrients calcium, 2.1 percent, sulfur,
.58 percent and magnesium, .68 percent, as well as 4 percent iron. It has traces of
other micronutrients, such as zinc, copper, boron and chloride.
Grass needs iron to make chlorophyll, necessary for photosynthesis. If the green
chlorophyll does not develop in young grass, the leaves look yellowish-green and
have yellow veins. This is called iron chlorosis.
Milorganite is made up of 85 percent organic material. Organic materials release
nutrients to plants over time, so are known as slow-release fertilizers. While
over-application of chemical fertilizers can burn plants, organic ingredients won’t.
Instead of a quick, chemical boost, microbes in the soil digest the nutrients in
Milorganite and deliver them to plants over a period of two to three months. The
nutrients stay in the soil until conditions are optimum for plants to take them up
during the growing season.
It can be applied anytime during the growing season because it doesn’t contain
anything that will burn grass. High temperatures, drought and rainfall do not prevent
Milorganite application. It does not need to be watered in, although during the dry
season, watering will push the material into the soil faster.
A high nitrogen count will cause your grass to become green such as in commercial
fertilizers. This will result in not only greener grass, but it will also
grow at an accelerated rate. This results in more frequent mowing. Milorganite contains a
much lower amount of nitrogen but adds iron, which keeps the grass green but does
not accelerate lawn growth. It is considered a slow-release fertilizer.
Milorganite is approved for home gardening use by the Environmental Protection Agency.
Milorganite is not toxic to humans or pets. Because its source is wastewater, however, it
may contain traces of pharmaceuticals. Because of Milorganite’s relatively high iron
content, it is likely to cause stomach upset and vomiting if a handful or more is eaten.
Store all fertilizers away from children and pets.
A recent study by the Sierra Club found that you may be unknowingly spreading PFAS chemicals
on your lawn and garden in the form of fertilizers made from bio-solids. Milorganite was one
of the fertilizers tested and shown PFAS concentrations.
Milwaukee Municipal Water District (MMWD) insists and Milorganite is safe to use.
Some PFAS were found in the popular fertilizer. PFOA and PFOS, two of the most well-researched
forms of the chemicals. PFOA was detected at 0.67 parts per billion, under 2.5 parts per billion limit.
PFOS, however, was detected at 8.66 parts per billion in Milorganite, over the 5.2 parts per billion
standard
The chemicals are persistent, remaining both in the environment and human body over time. Accumulation
of the chemicals in the body has been linked to cancer, studies have shown, or other adverse health effects.
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