Best Deer Repellent: What the Trials Rank First

A spray of 20 percent whole egg and 80 percent water. On Colorado State Extension's ranked repellent table it rates High, the top band, level with Deer Away Big Game Repellent, the best commercial product tested in the same program, and it costs about two dollars a batch. It needs reapplying in about thirty days. That is the answer for a garden under moderate pressure. For a planting you cannot afford to lose, the answer is a fence, and everything below is a way of postponing one.

The table

Fact sheet 6.520 from Colorado State is the one published ranking that scores home remedies and commercial products on the same captive-deer trials, so it is the table this page is built on.

Read down the column and the pattern is a mechanism. The products that scored High smell of something dead or of a predator. The middle band burns. The bottom band tastes bad. That order held in the largest head-to-head trial on record, the USDA National Wildlife Research Center's test of twenty commercial repellents on captive black-tailed deer over an eighteen-week winter: fear-inducing products beat pain and taste products, eight of the nine most effective over the first eleven weeks gave off sulfurous odors, and no product eliminated browsing.

What is in the bottle that works

Putrescent egg. Deer Away Big Game Repellent powder is 37 percent putrescent whole egg solids, and in the wildlife-damage literature it virtually eliminated browsing for four weeks and gave good protection for eight to twelve. The homemade version reaches the same rating with two eggs to a quart of water, strained, sprayed to runoff, repeated monthly.

Capsaicin. It works on deer and on nothing that flies, which is a real mechanism. The problem is dose: in the 1994 trial that tested a capsaicin repellent on captive mule deer, consumption at the labeled dilution did not differ from tap water, and only a dilution one hundred times stronger changed anything. Most bottles are dosed too low to matter. The 6.2 percent Hot Sauce entry in the table is the exception, and its label rate is the reason it is there.

Predator urine. Rated High at 100 percent. The bottle on the shelf holds about a twentieth of that, the EPA registered it without asking for efficacy data, and the compound responsible has never been identified. The full account is longer than the packaging.

Bobbex, Liquid Fence, Plantskydd. None of the three appears on the Colorado State table or in the twenty-product trial by name. Liquid Fence is putrescent egg and garlic and Plantskydd is dried blood, so both belong to the class that wins. No ranked trial consulted for this page places either, and this site does not rate what it cannot source.

Does Irish Spring soap repel deer?

Low to medium, in the one trial that scored bar soap, and the same Colorado State guidance records that deer have been reported to eat the bars. Hanging anything is the weak delivery: in the USDA trial, scent sachets reduced browsing only when they hung close enough to drip onto the foliage, and on stakes at half the plant's height they failed. The soap page has the rest.

What do farmers use to keep deer away?

Fences, mostly, because a repellent is priced per bed and a field is priced per acre. Penn State's guidance for fruit plantings puts the minimum at eight feet of woven wire for a larger area, and the electric alternative is a lower fence with strips of aluminum foil on the live wire, smeared with peanut butter, so the first contact is nose first and remembered. On food plots, the University of Georgia's soybean trial found Milorganite delayed browsing from about a week to more than five weeks before the deer came anyway. Sprays are for the beds that matter, not the acreage.

What do deer hate the most?

The smell of something dead. Decaying animal protein sat at the top of the USDA trial and putrescent egg is its retail form. Garlic is the widely repeated answer and it finished in the least effective tier in the same trial, both times it was the main ingredient; the garlic page is a correction of an earlier version of this site that said otherwise.

Will coffee grounds deter deer?

Nothing consulted for this page scores them. They are not on the Colorado State table, not in the twenty-product trial, and the extension guidance that discusses home remedies at all warns that "materials that work in one area or for one person may not work at all in an area more highly frequented by deer." Untested is not the same as useless. It is also not the same as working.

What to expect from the best one

Minnesota Extension sets the benchmark: a 50 percent reduction in browse is very successful, and 30 percent is the likelier result. That is for a whole program done properly, not for one product, and it is the figure to hold any bottle against.

Reapply the egg spray at about thirty days and after heavy rain. Rotate it with capsaicin so a deer meets a smell and a pain signal at once rather than getting used to either. The egg spray keeps working in cold weather, which the area repellents spread on the ground do not, and late winter is when the browsing that sends people to this page happens.

When to stop spraying

When losing a third of the planting is not survivable. At that point no scent product is the answer, the fence-height page is, and the cost page will price it.

One thing the trials do not settle. They were run on captive deer, mule deer and black-tailed deer for the most part, fed and watched. Whether a suburban whitetail with a bird feeder two yards over reads a rotten-egg spray the same way is not something any trial consulted here measured.