How to Get Rid of Roaches in Your Garage

A cockroach lying on its back, either dead or tired

Preiselbeere/Wikimedia Commons/CC BY-SA 2.0 DE

In This Article

Few people have trouble recognizing cockroaches. The insects that are common household pests in U.S. homes comprise roughly 30 different roach species found in several genera of the
Blattidae family of insects. There are several species of cockroach often battled by homeowners and apartment dwellers.

The American cockroach (Periplaneta americana), an insect that actually is a foreign invader from Africa and the Middle East. It averages about 1 1/2 inches in length at maturity and is reddish-brown in color with a flattened, oval body. Other common species of cockroaches that often invade homes include the German cockroach (Blatella germanica) and the oriental cockroach (Blatta orientalis). The German cockroach is a smaller, darker insect, less than 1 inch long. The oriental cockroach is about 1 inch long with a very dark brown or black color.

Whatever species you are dealing with, roaches are not a pleasant discovery in your garage. Feeding mostly on foods and other organic materials, roaches can transfer many pathogens from surface to surface, and they also contain certain protein substances that can cause severe allergic reactions in humans. Many allergies thought to be caused by dust mites are more likely caused by the dust of cockroach shells left behind from the six or seven molts by which young cockroaches become mature insects.

A brown cockroach with spiky legs on a tree branch

Paul Starosta / Getty Images

American cockroach (Periplaneta americana)
Andrew Waugh / Getty Images
German cockroach (Blattella germanica)
German cockroaches can spread disease and damage. by Lmbuga/wikipedia
Oriental cockroach
Oriental Cockroach Photo by Joaquim Alves Gaspar;

6 Ways to Get Rid of Cockroaches in the Garage

Keeping roaches at bay is an ongoing process and even clean houses get roaches sometimes. You may bring roach eggs in on used clothing, cardboard boxes, paper bags, or even your shoes, so don’t kick yourself too hard if your garage develops a cockroach problem. To win the cockroach battle, you’ll have to do some spring cleaning. Often, if you eliminate the areas giving the roaches safe harbor, they’ll move or die out from lack of food and water.

Eliminate Cardboard and Paper

Innocuous cardboard boxes, paper bags, and stored magazines, books, or newspapers are breeding grounds for cockroaches and some other insects. Cockroaches are well-equipped to use the starches in the adhesives on these paper items as food and seem to be drawn to them as a place to lay their eggs. Start your cockroach elimination efforts by moving everything in bags and boxes into air-tight plastic storage. You may find a few dead roaches next time you break the seal, but that should be the last of them.

Rinse Out Recyclables

Many people recycle without rinsing their containers first—this is a terrible idea if you’ve got roach problems.  Even if you bag up your recyclables, roaches can get inside and will readily eat the remaining food. Remember, these primitive little creatures can use just about anything as a food source, so start rinsing out any recyclable items and allow them to dry if you must store them in the garage. Even better is to move recycling bins outdoors.

Move Garbage

Out of sight is out of mind, but if you stash your trash in the garage between pickups, you’re opening an all-you-can-eat buffet for cockroaches. Get that trash outside right away. If you’re worried about animals spilling the garbage can, use a bungee to keep the lid tightly attached.

Eliminate Sources of Moisture

Drippy hoses and leaky hot water heaters can contribute more than enough moisture to the garage to support a large extended family of roaches. Dry up these areas and you’ll remove much-needed moisture. Like many insects, cockroaches can’t survive without adequate water and humidity.

Set Roach Traps

Roach traps are the most common means of controlling roaches. They are sometimes marketing with catchy names, such as "roach motels." There are two types of roach traps: those that lure in the roaches and trap them so you can physically dispose of them, and those that lure them in with a food substance, usually sugary, that is laced with boric acid or another chemical that interferes with the reproductive cycle of the insects.

Other traps use chemicals such as hydramethylnon, which is a slow-acting toxin. The roaches ingest the poison, then travel back to nests where they die and are often eaten by other roaches, thereby spreading the poison. Such products are often in gel form. Hydramethylnon is listed as a potential carcinogen, so should be used as a last resort, and only where you can protect humans and pets from accidental contact.

Use Sprays or Foggers

Spraying visible roaches with a pesticide is often easier in a garage than it is in other spaces. Sprays normally use pyrethroid chemicals to shut down the roach’s nervous system. Don't worry if the spray doesn't seem to kill the roaches instantly; it can take up to a week to kill roaches this way.

Another option is to use a fogger or "bug bomb," which works by putting a fog of pesticide into the air, where it infiltrates cracks and walls to kill hidden roaches. Sprays and foggers normally also use pyrethroid chemicals to shut down the roach’s nervous system.

Pyrethroids are often marketed as environmentally safe pesticides since they are similar to pyrethrin, a natural substance derived from the flowers of chrysanthemums. But pyrethroids are a synthetic form to which certain chemicals are added to improve the product's effectiveness.

Caution

Pyrethroid and pyrethrin pesticides are quite toxic to fish and other aquatic life, and they are not completely harmless to people and animals. When using a pyrethroid or pyrethrin fogger, the space should be vacated for at least four hours, then completely ventilated before people or pets are allowed back in.

What Causes Cockroaches in the Garage?

Roaches need three things to survive: warmth, moisture, and food. Different species have specific needs, but in general, if you want to find where the roaches are hiding in your garage, check out areas where it’s dark and humid. Garbage cans and recyclables that aren’t rinsed before storing provide ample food sources for cockroaches, who may nest nearby.

Sometimes, cockroaches in the garage are simply wayward wanderers who managed to squeeze in during the night, so don’t panic if you only see one cockroach in your garage and can’t find his lair. He may just be passing through—a swift dispatch with your shoe, if you’re compelled, will take care of him.

How to Prevent Roaches in the Garage

You can prevent new infestations by continuing to follow some of the strategies for elimination. In addition, periodically inspect and repair your garage door seals, caulking the trim around the doors and windows in your garage, and leaving cardboard boxes and paper bags outdoors.

Good sanitation is the key to preventing roaches from infiltrating any space. If you keep your garage free of foods and other organic materials, and as dry as possible, roaches are unlikely to be a big problem. Pay particular attention to ground-level areas, where boxes and other materials are stored in contact with a concrete slab floor. Keeping the slab clean and dry will cause roaches to look elsewhere for favorable habitat.

FAQs

Do Cockroaches Carry Diseases?

Roaches have been linked to asthma and a variety of food-borne illnesses. Roaches can transmit bacteria and other pathogens from surface to surface as they feed on decayed foods and other organic materials.

Do Cockroaches Bite?

Though it's rare, cockroaches can bite through skin. This is quite uncommon, though, and most bites attributed to cockroaches are inflicted by spiders or various insects.

Will Cockroaches Go Away on Their Own?

Cockroaches may vacate a space if they stop finding the moisture and edible materials they need to survive. Otherwise, they will continue to live, reproduce, and proliferate as long as there is moisture and organic material on which to feed. This is an opportunistic insect that does appear in cycles like some other insects, but rather it thrives wherever suitable living conditions are found.

How Long Do Cockroaches Live?

Cockroaches typically live about 12 to 18 months. But when given the right environment, they reproduce so readily that it may seem like cockroacshes are practically eternal.

What Do Young Cockroaches Look Like?

Upon hatching, cockroaches are initially bright white nymphs, but within a few hours, they have swelled into a version that looks much like an adult insect, though slightly lighter in color. Through a series of six or seven molts over three or four months, the insect gradually grows into a mature reproducing insect.

Do Cockroaches Fly?

Most species of cockroaches, including the American cockroach, have wings that they keep folded over their backs. They are able to fly but rarely do, preferring instead to crawl. The wings are evident only in mature insects.