You’ve just discovered signs of a mouse or rat infestation in your home, now what? You might want to call an exterminator, or simply head to the nearest store that carries rodent poison. But what if you want to use a potentially safer method than poison to deal with the little critters?
Nowadays though, many of us are concerned about the effects of toxic chemicals on ourselves, our children, and the environment in general. If you are looking for an alternative to toxic methods of rodent removal there are a few science-tested natural remedies you can try.
Citronella oil as a natural repellant for many insects and rodents, but does citronella oil repel mice and rats? Citronella oil is a great way to repel rats and mice as long as the solution you use has at least 10% citronella oil.
How to Use Citronella Oil to Repel Rats and Mice
Scientists studied the ability of various essential oils, including citronella, to repel rats by spraying the diluted oils either in the rat’s normal path or on food items. Concentrations of 5%, 10%, and 20% were tested.
In a test that specifically used citronella oil, the scientists tested reapplying the solution daily, every other day, and once a week. The citronella oil was dissolved in isopropyl alcohol and painted inside enclosures where food was placed for the rats. The amount of food the rats ate from each enclosure was measured with and without citronella oil in place, and at the various concentrations and times applied.
The best repellent results were seen with 10% citronella solution applied daily. This is likely because essential oils evaporate quickly and the smell doesn’t persist at a strong enough concentration to be effective after a day or two.
To be most effective the citronella spray must be applied where the rodents will come into direct contact with it. There is a method described wherein cotton balls are soaked in the oil solution and placed in the pathways of the mice and rats, or where feces or other signs are observed.
This doesn’t work as well as the spray, perhaps because the smell is not strong enough, or the cotton ball is small enough to dodge around while still remaining on their safe path.
You can make citronella (or other essential oil sprays) by mixing 1 ½ Tablespoons of essential oil into 1 cup of rubbing alcohol in a spray bottle. Spray liberally wherever you see traces of rodents or think their paths may be.
We recommend using pure and undiluted citronella oil like this one, as it will have the best effects when making your own citronella spray.
What Other Essential Oils Repel Mice?
In another study, also done on rats, various essential oils were tested singly and in combination. The oils were sprayed on pieces of cardboard paper and placed where the rats would normally interact with them. Then the pieces of cardboard were examined to see if they had been chewed by the rats or left alone.
The oils tested were wintergreen oil, chili oil, bergamot oil, peppermint oil, and geranium oil. The combinations used were chili+wintergreen, peppermint+wintergreen, peppermint+wintergreen+bergamot, bergamot+geranium, and bergamot alone.
The degree of cardboard destruction varied quite a lot, perhaps due to different rat’s personal tolerances. But it was found that chili+wintergreen and peppermint+wintergreen+bergamot consistently showed no signs of being torn or chewed by the rats.
The cardboard that had been sprayed with bergamot+geranium oil showed less chewing and tearing than the ones sprayed with peppermint+wintergreen oil, bergamot only, or no oil.
Signs of Mice or Rats
One of the surest signs of rodents living in your space is their droppings. You can get a good idea of the type of rodent, as well as how many there are, and where they hang out the most, by observing their droppings.
Mouse droppings are tiny, less than ¼ inch long, and pointed at both ends. Rat droppings are at least twice the size of mouse droppings, proportionally fatter, and can be pointed at the ends or blunt, depending on the species of rat.
Fresh rodent droppings are shiny and pliable, while old droppings are harder and crumbly. If you see varying dropping sizes together it likely means that there are both adults and juveniles living there. Many droppings may indicate a large infestation.
Scratching and scrabbling noises heard at night, inside walls and along the edges of floors, may be an indication of a rodent infestation. Occasionally squeaking can be heard as well. If you hear squeaking or scratching noises inside your walls start checking for other rodent signs.
Rub Marks or Tracks
Mice and rats will often run along the wall or another sheltered area sticking close to cover and safety. Sometimes they leave greasy rub marks or oily smears along the bottoms of walls or near baseboards or other cover. Check carefully for these marks.
If the rub marks smear and appear fresh they could have been left by rodents. Of course, the marks could be made by something else. Try cleaning an area and see if the marks reappear.
Check dusty areas for tiny footprints or lines from dragging tails. Along baseboards, under the edges of cupboards, in corners, etc. You may be able to see where the mice or rats are coming and going.
Gnawed Wood or Drywall
Mice and rats have teeth that never stop growing and they are constantly gnawing on things to help wear their teeth down. They also chew and gnaw things to gather nesting materials, and chew holes in walls to make passages.
Teeth marks made by rats will usually be about 1/8 inch long. Holes gnawed by rats will be about the size of a quarter with ragged edges. Small scratch-looking teeth marks are usually made by mice. Holes gnawed by them will be small, about the size of a dime, and clean around the edges.
Mice will nest indoors and use shredded paper, yarn or string, and other soft materials to make their nests. Some rats nest outside in burrows and others nest in attics or trees.
Smelling a heavy, musky odor all of a sudden? It could be rodent urine from a large infestation.
Your pets may give you signals that some other creature is sharing your living space. Dogs and cats may stare fixedly at spaces underneath appliances or furniture, or attempt to get underneath them. Dogs may bark, cats may go into hunting mode.
Maybe some evening you stepped into the kitchen in the dark for a drink of water and saw something scuttling along the wall or under the edge of the cupboard!
Mice are tiny, about 3 to 4 inches long, with about the same amount of hairless tail, and move incredibly quickly for their size. They only weigh between ½ and 1 oz, about as much as 5 to 10 pennies. They have fine, soft fur that is grey, brown, or black, large ears, and tiny black eyes.
Rats are much larger than mice, with a body that is 7 to 11 inches long, and a scaly, hairless tail that is 5 to 9 inches long. They weigh from ½ to 1 pound. Their fur is coarser than that of mice and can be brown, reddish, black, or gray.
Essential oils can work to keep mice and rats away, but they must be applied frequently directly to the area the rodents are using. Once the little critters have been chased off you’ll need to take measures to keep them out or they will soon be back.
Cover any possible entrances with sheet metal or stuff small holes with steel wool to keep mice and rats out. Remember, mice can fit through holes the size of a dime!
If you’ve had problems with mice and rats be sure to keep all food items in rodent-proof containers. Clean up all food spills and crumbs from counters and floors immediately and thoroughly as rodents have great senses of smell and will come looking for anything yummy they can sense.