Repellents
How They Work
Repellents work by emitting an alarming odor or bad taste that repels deer. They make treated plants less palatable and less desirable to deer. They have been used successfully to reduce damage to ornamental plants, vegetable gardens, orchards, and tree and landscape nurseries.
Repellents do not alter the aesthetics of plantings, and can be used where aesthetics cannot be compromised. They are effective when used in areas with low to moderate deer numbers. Repellents are most effective where untreated plants are available for to deer. Repellents should not be expected to eliminate all damage, but they can help to reduce deer feeding damage to plantings. Some repellents are applied directly to plants and some are placed near plants that need protection. Repellents should only be applied according to label directions, to prevent damage to tender plantings. Most repellents can be placed into two categories, taste-based repellents and odor-based repellents, though a few repellents incorporate some of both qualities.
Taste-Based Repellents
Taste-based repellents impart a noxious taste that makes treated plants less palatable than untreated plants. Most taste-based repellents are applied directly to each individual plant and discourage deer from feeding because of the offensive taste that they impart to the plant. One kind of taste-based repellent is systemic. It is placed in the ground with the plant roots, and is absorbed by the plant as it grows. The chemicals absorbed by the plant impart a noxious taste to the plant, which deters deer feeding. A drawback of taste-based repellents is that deer must eat part of the plant before being repelled.
Certain taste-based repellents can be used on edible plants such as vegetable crops, fruits, berries, nuts and herbs, but they must be removed (washed off) prior to eating.
The following repellents are approved for use on edible plants:
Only those repellents that are labeled for use on edible plants should be used for edible plants.
Odor-Based Repellents
Odor-based repellents capitalize on a deer’s keen sense of smell. Their odor discourages deer from feeding on the treated plants by producing an offensive or alarming odor, which repels deer. Some odor-based repellents can be placed into dispensers that can be attached to or near plants. The Plant Pro-Tec Garlic Dispenser is one repellent dispenser that is clipped onto edible plants and doesn’t need to be washed off because it isn’t directly applied to the plant. Some odor-based repellents may use rotten eggs, animal parts, and soaps as active ingredients. Some incorporate chemicals that deer find offensive. Still, other odor-based repellents use real or synthetic predator urines to repel deer. Repellents that use predator urines rely on the principle that large predators mark their territory with their urine, and that deer are discouraged from entering areas frequented by these predators.
Odor-based repellents can be used to treat individual plants or for area treatments. One system of area treatment is called the rope fence system. This treatment is done by suspending a single-strand of cotton rope, at waist height, on fence posts or stakes anchored around the perimeter of the impacted area. The rope is treated with an odor-based repellent that discourages deer from entering the fenced area. The Plot Saver system by Big Bucks Enterprises is an example of a commercial product that employs this concept. A similar method is done using strips of cloth or dryer sheets treated with an odor-based repellent attached to stakes placed in the ground around the area to be protected.
Homemade vs. Commercial Repellents
Repellents can be purchased commercially or they can be homemade. Homemade repellents can be inexpensive, but may not be as effective as some commercial repellents. Some examples of homemade repellents include human hair clippings in a mesh bag, crushed garlic cloves in a cloth bag, and deodorant soap attached to the plant by a string.
Commercial repellents can be more expensive than homemade ones, but most of them have the advantage of being tested and developed for effectiveness. Newer repellent technology has incorporated sticking agents that adhere the repellents to the plants, making them last longer before needing reapplication. Some commercial repellents are reported to have worked for up to five weeks, before needing reapplication. Commercial repellents come in many different forms. Some come as solids that must be dusted on plants, some are solids or liquid concentrates that must be mixed with water to form a solution, and others come pre-mixed and ready for use. Liquid repellents can be easily applied using a spray bottle or pump sprayer.
Repellents: Drawbacks
Some drawbacks of repellents are: they can be costly, they need to be reapplied after repeated exposure to the weather and, they can loose their effectiveness as deer can learn to tolerate them, especially when food is in short supply. Repellents can be ineffective at deterring antler rubbing by deer. During the fall, male deer rub their antlers on trees to remove velvet, to polish their antlers, and to mark their territory. Plant enclosures like wire cages or tree shelters can be used to deter antler rub damage.
Repellents should be applied at the first sign of damage or if damage is expected, prior to any damage. Deer may eat plants that have been treated with repellents, if alternative foods are not available. Snow cover can prevent deer from finding food, which can encourage them feed on treated plants. Deer can become used to some repellents over time. Repellents degrade and need reapplication.
Not all repellents perform equally - some repellents are more effective than others at deterring deer damage. Using different repellents can prevent deer from becoming used to any one kind, and can be more effective than using just one kind. Due to their cost and varying effectiveness, repellents should only be considered as a method of reducing deer damage. Where larger areas need protection, other deterrents, exclusion or a combination of damage abatement measures should be considered. Weather, adjacent natural habitat and deer numbers influence the effectiveness of most repellents.
Repellents: Advantages
Repellents can reduce deer damage to tolerable levels in areas where damage pressure is light to moderate. They can be a cost-effective treatment for reducing deer damage on small to medium-sized areas such as gardens, landscape plantings, small orchards and small to medium-sized tree and landscape nurseries. Repellents do not alter the appearance of landscape plantings and should be considered where exclusion methods would detract from the aesthetics of plantings. Commercial repellents are readily available at various retailers, and can even be ordered online. Advancements in repellent technology have resulted in repellents that last for up to five weeks before needing reapplication. Most repellents are easily mixed and applied, and some come premixed and ready to use, in handy spray bottles.
Repellents are most effective when they are used in conjunction with other deer damage management techniques, like fencing and population reduction.
List Of Repellents:
The following list contains both commercial and homemade repellents that have been used with success to reduce deer damage.
Commercial Repellents
(* Repellents marked with an asterisk denote that they are a repellent that can be used on edible plants. Remember to always follow the label instructions.)
Deer Away / Big Game Repellent - Deer Off - Ro-pel - Thiram - Tree Guard Deer Busters – Deer Stoppers – Liquid Fence Animal Repellent – Bobbex Plantskydd - Repel Bye Deer – Magic Circle Deer – Green Screen – Garden Thunder - Deer Chaser - Deer No – Havahart Deer and Rabbit Repellent - Not Tonight Deer Get Away – Holly Ridge – Dr. T’s Deer Blocker Hinder* - Millers’ Hot Sauce * - Deer Stopper* - Plant Pro-Tec Garlic Dispensers* - Milorganite fertilizer spread on ground around plants or placed in bags suspended from plants
Homemade Repellents
Ammonia soaked rags tied to/near plants or suspended by stakes
Human hair (2 handfuls) in mesh bag
Worn clothes (with human odor) hung near plants
Predator urine sprinkled on ground or cloths around plants
Tankage (putrified meat scraps) sprayed on ground around plants
Rotten eggs placed in vicinity of plants
Egg/water mixture (4 to 6 raw eggs mixed with 1 gallon water) sprayed on non-edible plants
Hot pepper spray - 2 tbsp. hot pepper mixed with 1 tbsp. liquid dish soap, 1 tsp. garlic powder, to 1gal.water
Blood meal or Bone meal scattered around plants on ground
Deodorant Soap (any fragrant deodorant soap); shavings scattered on ground around plants; bar of soap hung from plants by a string
Repellents can be purchased at many nurseries, home and garden stores, home improvement stores, and some hardware stores, and can even be purchased online at various websites, and through mail-order catalogues.
