Research conducted at the University of Georgia suggests that Milorganite is a useful tool in repelling deer from grazing on food plots and ornamental plantings.
• Research indicates Milorganite's odor is effective in reducing deer from browsing on plants up to 5 weeks.
• Spread Milorganite around your plantings to deter deer at an application rate of one-half cup per plant.
• The study concluded plant damage may be reduced if Milorganite is reapplied every 14 days. Results may vary.
Consumer media has for many years published anecdotal information indicating Milorganite‘s efficacy as a garden pest deterrent.
"It is widely agreed that scent-based repellents are an effective, albeit temporary deterrent to deer and certain other creatures. I was anxious to put my idea to the test using Milorganite, a natural, nitrogen based fertilizer that also has the reputation and added benefit of acting as a repellent to deer". "Controlling Deer in My Garden" by Joe Lamp'l Gardening Expert and Host of Growing a Greener World®
We first heard of Milorganite for deer repellent from an old-timer at a local supply store. I asked him what he used to keep deer out and whether he used fencing, and he said “No, no.. Milorganite.”
So we bought some for deer repellent, only to discover another benefit: Milorganite is a deer repellent and fertilizer! Now we use Milorganite as a fertilizer that also repels deer. Deer Repellent: How to Keep Deer out of the Garden By Coleman Alderson from GardensAll.com
“There are some effective products that can keep deer out of your landscape up to 90 days. These products include Milorganite.” Be ready for the return of bugs and critters by Denny McKeown.
"It makes a great lawn fertilizer and can aid as a deer deterrent from browsing on your prized landscape plants while feeding at the same time." Rick Vuyst Garden Host and CEO of Flowerland Garden Centers
Why is Milorganite not registered and marketed as a deer repellent?
In 2009, the U.S. Environmental Protection Agency (EPA) Biopesticides and Pollution Prevention Division (BPPD) required Milorganite to complete additional environmental and health tests, which would have cost $1–2 million and take years to complete. These tests would not have guaranteed approval to market Milorganite as a deer repellent. Milorganite is a public entity, owned and operated by the Milwaukee Metropolitan Sewage District (MMSD) and it was decided it wasn’t in the best interest of the community to spend millions of dollars without a guaranteed return on investment. Therefore, the use of Milorganite as an animal deterrent is an off-label use.