Do Animal Repellents Really Work?


Animals and birds are cute as buttons, but what damage they can cause to gardens!

Probably every gardener will have to deal with an undesirable animal or bird at some point: a groundhog grazing on their broccoli, birds eating their seedlings, a cat using the vegetable bed as a litter box, and so on. If so, no worry: there is a whole range of animal deterrents you can try, products that are supposed to drive them away. But are they effective?

There are dozens of these products on the market and just as many homemade deterrents: plastic owls or snakes, silver ribbons or aluminum pie plates that move in the wind, systems that produce loud noises or ultrasounds, stinky products like rotten eggs, predator urine and animal fur, good old-fashioned scarecrows, and the list goes on.

Deterrents function by scaring mammals (and also birds in some cases): they make the animal feel that there is something strange or abnormal going on and it feels threatened, staying away for a while. And that’s where the problem lies: there really is no threat and, once the animal realizes that there is no real danger, it comes back to its former haunts.

The secret, therefore, is not to have a single repellent or deterrent, but several, and to use them in rotation. Normally, a deterrent will be effective for about two weeks. That means you’ll need a whole arsenal of repellents if you want to spend a summer in peace.

Here are a few:


A scarecrow will work for a while … but not the whole summer! Photo: En: User: Fg2, Wikipedia

  • Aluminum plates or metal cans attached to strings so they bang together in the wind;
  • Animal decoys (owls, snakes, hawks, coyotes, etc.);
  • Bits of cloth soaked in creosote;
  • Blood meal or chicken manure (and they’re fertilizers too!);
  • Bright light set off by a motion detector;
  • Cat or dog fur (get some from a pet groomer);
  • Commercial animal repellents (Plantskydd, Bobbex, etc.);
  • Garlic spray;
  • Highly perfumed fabric softener sheets;
  • Human hair (ask your hairdresser to save some for you);
  • Irish Spring, Dial or any other strongly scented soap;
  • Loud music;
  • Moth balls (be careful not to leave them where kids or pets can get to them!);
  • Motion-activated sprinkler;
  • Predator urine (coyote, fox and even lion urine can be purchased);
  • Recordings of explosions or rifle shots;
  • Repellent plants (dill, chives, garlic, lavender, onion, oregano, Russian sage, tansy, tarragon, thyme, wormwood and yarrow are examples: they’ll avoid these plants … for a while!);
  • Scarecrows;
  • Scare-eye balloons;
  • Shiny ribbons that dangle from branches or wires;
  • Sprays made from rotten eggs;
  • Treated sewage sludge (Milorganite, for example);
  • Ultrasonic devices (actually, though widely available, they have not been found very effective);
  • White rags that move in the wind;
  • And so on.

Note that many of these repellents smell so badly or make so much noise that you won’t want to visit your garden either!

The Only Deterrent That Works Long Term


A motion-activated sprinkler will scare pests away every time.

Other than properly installed animal fencing (very expensive and difficult to properly install, but permanent and effective), the only simple deterrent that keeps most animals away in the long run is the motion-activated sprinkler. The animal approaches your garden and gets sprayed. True enough, it’s only with water, but … something has touched it and that is something no animal seems to be able to get used to. Deer, raccoons, cats, dogs, squirrels, rabbits, groundhogs, even crows and pigeons: they’ll all stay away from a motion-activated sprinkler.

Obviously, the device is not effective against animals that live underground, such as moles, and doesn’t react to very small animals: chipmunks, mice, most birds, etc. And at about $70 per device, it’s quite expensive … but at least it works and thus you rarely hear a user complain about the price. Apparently peace between humans and animals is worth any expense!20170605A

Keep Cats Out of Your Garden


Cats can be charming and friendly… yet a disaster in the garden!

You just love your cat! He (or she) is smart and affectionate and would never hurt a fly, let alone a garden. But the neighbor’s cat, that’s a different story. The @*&#! thing has decided your garden is it’s personal litter box. And your other neighbor feeds stray cats and attracts dozens to the neighborhood where they spray your plants with stinky urine, defecate in your garden, and dig up your beds. What can you do?

Fortunately, there are several tricks you can use to keep cats away from a yard. Here are a few:

  1. Keep the animals’ favorite litter spot moist by repeatedly watering it: cats hate getting their paws wet.
  2. Cover the soil with chicken wire. Cats won’t be able to dig into the soil and in fact won’t even walk on it, yet plants can grow through the mesh.
  3. Cover the soil with a rough or even prickly mulch: bark mulch, pinecones, spruce branches, rose trimmings, gravel, etc. They’ll keep cats away.
  4. Apply dog hair to the spot (kitty won’t be happy with that!). If you don’t have a pooch, ask a dog grooming salon for a few handfuls. Human hair will work too… on feral cats. Domestic cats, though, are not bothered by human odors.
  5. Apply citrus peels to the soil. Kitties will avoid them.


    Barriers that poke out of the ground will keep cats at bay.

  6. Stick coffee stirrers, bamboo skewers, or plastic forks (pointy side up) about 8 inches (20 cm) apart in the soil of the cat’s favorite litter area. This will make things very uncomfortable for Puss.


    The Piss-off Plant won’t actually repel cats at all.

  7. Some plants have the reputation of being able to repel cats. This is particularly the case of rue (Ruta graveolens), lavender (Lavandula spp.), pennyroyal (Mentha pulegium), absinthe (Artemisia absinthium), lemon thyme (Thymus x citriodorus), lemon balm (Melissa officinalis) and Piss-off Plant™ (Coleus canina, now Plectranthus caninus, also sold under names Scaredy Cat™, Dog’s Gone™ or Bunnies Gone™). Be forewarned though that some cats seem fairly indifferent to plant odors: you may have to test several plants to find one that works in your situation. And very honestly, the so-called Piss-off Plant (P. caninus) has a terrible reputation among gardeners. In fact, serious studies show it simply doesn’t work.
  8. Use a commercial animal repellent, which can be coyote urine or the urine of some other predator, rotten eggs, or a mixture of various repellent products. You can spray it on the soil or on the surrounding plants or structures. You’ll have to spray repeatedly (read the instructions for the recommended frequency of application), as they wear off. Sometimes you have to try several repellents before finding one that works well.
  9. Surround the garden with fencing. This is an expensive solution, but if you have to protect an entire garden from feral cats, it may be the best choice. Use chicken wire, plastic mesh or chain link fence on metal or plastic posts (cats will climb wooden ones). The fence should be at least 7 feet (2 m) high and buried at the base (the cats won’t hesitate to dig to reach their favorite garden). An electric fence is another possibility.
  10. Install an ultrasound repulsive device. These seem to work with most cats at first, but most cats eventually get used to it, so it may only be a temporary solution.


    The Scarecrow motion-activated sprinkler is very effective at chasing cats from gardens.

  11. Use a motion-activated sprinkler. Just attach it to a hose and point it towards the garden in question. The next time the cat saunters by, it’ll be greeted with a spray of water, the ultimate insult for kitties! This method seems completely effective, but the device is quite pricey. Two models I know of are the Scarecrow by Contech and Spray Away by Havahart.

Methods to Avoid

On the Internet, you’ll find dozens of other methods for keeping cats away from your garden, some effective, some slightly so, and many a waste of time, but there are a few you should simply avoid. Here are some examples:


Mothballs are toxic products and have no place in the garden.

Placing mothballs in the garden. Their odor is said to repel cats (that in itself is debatable), but the real problem is that they contain naphthalene, a toxic product. Some cats, far from being repelled, eat the mothballs and make themselves sick. Some even die. Also, children may mistake them for candy.

The same applies to dryer sheets (Bounce, Snuggle, etc.), also sometimes recommended for keeping cats away. Some cats chew or play with them and make themselves sick.

Another product that is supposed to repel cats (again, very debatable), but can poison them instead is ammonia. Especially don’t put out a dish of ammonia: some cats are actually attracted to ammonia and may poison themselves by drinking it.

One of the most horrifying means of repelling cats is sprinkling the ground with cayenne pepper. It’s not only ineffective (cats are not repulsed by cayenne pepper and in fact, don’t even seem to notice it’s there), but it’s downright nasty. The cat’s paws pick up the powder, then, when it licks itself to clean up, it will be in serious pain. The pain will be worse if the pepper gets it in its eyes. And when swallowed, cayenne pepper can cause severe intestinal distress in cats. Too many cats end up at the vet’s after coming into contact with this product.

Finally, it is sometimes said that applying coffee grounds to the soil will repel cats. While coffee grounds aren’t harmful to cats, using them this way is a waste of time. Most cats are indifferent to coffee grounds while others are actually attracted to the stuff. Just put your coffee grounds in the compost bin, where they really belong!