Vertebrates in the Vegetables!
By Dr. Jim Pease, Emeritus
Extension Wildlife Specialist (ISU - Retired)
This is a frustrating time of year for many gardeners. After working hard all spring to get plants and seeds into the ground, fighting the weather, and conquering the weeds, the harvest has begun. But, just as the beans begin to bear and the hostas bloom, some other vertebrate critters begin to harvest the plants as well. Rabbits, ground squirrels, tree squirrels, pocket gophers, or deer arrive to take advantage of the plantings you have provided--assuming that you have provided food just for them! Like many staff from Extension offices or county conservation boards, I receive the phone calls from these frustrated gardeners. Usually they begin with something like: "ARRGH!"
The two major defenses gardeners have against such competition are: repellents and exclusion. Repellents are either area repellents or taste repellents. Area repellents repel the animal by smell. As the name implies, the chemical is aromatic and fills the air in the general area of the planting. The smell is offensive to the animal and it avoids the area. Examples of such repellents include hanging bags of human hair or bars of soap or commercial products like moth balls (naphthalene).
Taste repellents are more effective in that they are applied directly to the plant and repel the animal by having a bad taste. The idea is that the animal may sample the plant once, but the bad taste keeps it from trying it again. Examples include such "home remedies" as cayenne pepper and commercial products containing such chemicals as thiram, putrescent egg solids, or other foul-tasting products. Some plants appear to naturally contain chemicals that are repellents to browsing by deer, rabbits, or other animals.
Repellents are not, however, a cure-all. Area repellents are limited in effectiveness, but may be useful if placed around the perimeter of the garden area. Taste repellents cannot be applied to plants you intend to eat since you would also find the taste offensive. Most repellents must be reapplied regularly, especially after rain or periods of extreme heat. Not all products are registered for or effective against all species. And, if an animal is hungry enough, they will often ignore the bad smell or taste. Despite these limitations, many gardeners may find repellents to be the best alternative in their particular circumstance.
Another more permanent protection against unwanted sampling of your garden is exclusion. You may exclude in several ways, depending upon the area you are in and the situation. Individual plants may be surrounded by plastic tubes, chicken wire, or hardware cloth fences. You may also fence off your whole garden area to exclude the worst offenders. When my family moved back to a rural area a few years ago, the first thing we did to our new garden plot--before we put a single seed or plant in the ground--was to fence it against rabbits and deer. We still have the occasional plant lost to a chipmunk since they can climb the fence. But that level of damage is tolerable. Rabbit and deer damage could be total if they were not fenced out.
The size and mesh of the fence depend upon what you are trying to exclude. For rabbits, 1-inch mesh "chicken-wire" fence at least 2 feet high will successfully exclude them, especially if the bottom 2-3 inches are buried below ground level. For deer, you may use a variety of fences including electrical tape or strong large mesh of any kind. Old "hog wire" fencing filling many farm gullies will suffice, especially if several sections are erected, reaching a height of 8 feet. In small garden plots, you may be successful with fences somewhat shorter than that, but no lower than 5-6 feet.
Gardeners may find also that general clean-up of garden areas will eliminate the brush, log, or junk piles that provide protective cover for many of the offending critters. Also, the presence of pet dogs and cats will often serve as an aversion to these wildlife. Be sure that local leash laws are followed.
Above all, keep in mind that your gardens are often planted as attractants to wildlife. Unfortunately, it will attract both those critters you want and those you don't. Some damage should be expected. When your tolerance level for such damage cannot be raised any higher, then try some of these repellent or exclusion methods.
Photo Credit: Eastern Cottontail - US Fish and Wildlife Service, National Digital Library - photo taken by William R. James