And 3 percent of whatever is in the bag is pure nitrogen, and the rest is organic matter, which helps release nitrogen. Other fertilizer mixes with Milorganite before University grounds crew members apply it to lawns and gardens. Although the organic alternative can work alone, the addition of conventional fertilizers reduces costs and the number of necessary applications. Increasing nitrogen levels without using damaging salts is one of Milorganite's advantages. Most fertilizers slowly release nitrogen with salt.
Salt burns foliage, turning it brown.
Although made from raw sewage, Milorganite safely fertilizes lawns, said Carl Rosen, University soil, water and climate professor. The filtration process kills off any potential disease-causing pathogens using heat. While Milorganite meets all of the Environmental Protection Agency requirements, Rosen warns against using it on vegetable gardens. Because production of Milorganite takes place in an industrial area, many heavier metals can mix into the fertilizer and create a hazard to food safety, he said. But because Milorganite is organic, it decreases the chance of ground water contamination, said Patrick Weicherding, University horticulture professor.