Dear Iris

Repelling garden pests naturally 

Jul 26, 2012

Did you know that the metabolic rate of rodents (squirrels, voles, muskrats, beavers, chipmunks, woodchucks, gophers, mice, rats, and shrews) is so high that they must eat almost constantly to sustain themselves? They are the most numerous of Iowa’s wild mammals and share ranks with birds, moles, rabbits, raccoons, and deer as unwanted garden visitors. Repellants, scare tactics, traps, and barriers are all natural ways of repelling your varied garden invaders.

Repellants: Everyone has heard of blood meal or human hair sprinkled around the garden, but have you heard of bars of strong smelling soap such as Irish Spring spread helter skelter on the ground or in little net bags or formerly discarded plastic berry containers from the store? Carnivorous human male 1st urine of the day or predator urine or any other strong offense odor on a rag here and there on the garden fence or distributed around the garden perimeter is a strong deterrent as long as it is reapplied every two weeks and after every rain. Cayenne pepper liberally sprinkled on wet leaves will deter even the most determined garden pests. The very tall and pretty but lethal castor bean plants and seeds deter birds, moles and deer. Always wear gloves when handling any root, leaf, flower or seed from this deadly plant!

 Scare tactics: Reflective items such as aluminum foil or discarded cds/dvds randomly startle intruders. Fake owls or toy snakes here and there in the garden that are periodically moved around tend to keep birds and small animals at bay. A scarecrow will also keep those smaller animals away and sometimes the larger ones as well. Noise makers such as chimes, dogs, radios on timers or empty plastic bottles over garden stakes also chase away intruders.

Traps: Trap crops are plants sacrificed so the intruder will stay away from the crop you really want to harvest, such as planting some lettuce near invader burrows. With a bit of luck, rabbits and woodchucks will eat “their” lettuce instead of yours. Conventional traps whether kind or harmful are also options.

Barriers: Barriers include netting, natural barriers and fences. Draping a net over fruit trees/bushes/plants or over hoops secured over rows in the garden work well to protect from birds, and less adventurous animals. Shrubs or an old fashioned moat will deter many walking pests. Fences seem to work best for most people for most types of garden invaders. If the bottom edge of the fence (at least 10”) is buried underground and the rest (3’ for small animals and 8’ for deer) is above ground, the number of pests in your garden will be substantially reduced. To increase the chances of keeping out all deer, place another fence no more than 3 inches inside of the outer fence because they will not have enough room to land from the first jump and make the second one.

Every tactic you undertake involves time and perhaps also money, so it is important to first identify who your garden invaders are and then “chose your weapons.” Remember that your unwanted visitors are shrewd. If you periodically change your tactics using any combination of the suggestions here or in part I printed May 31 in The Fairfield Ledger, your efforts will be rewarded and your plants will be the healthiest and happiest you’ve ever grown.

Aideen Vega-Van Auken is a Master Gardener.