Why Do I Have Cockroaches In My Garage [Reasons To Know]

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So, did you see a few fat cockroaches while parking the car? Yeah, I know cockroaches are nasty. Even seeing one in the house will make you worried. Are you thinking, Why Do I have cockroaches in my garage? Because cockroaches, search for dark and humid places to nest and your garage is an ideal nesting place with little to no human interference. 

Try these tested tips to keep your garage cockroaches free:

  • Remove All The Food Sources
  • Stop The Water Supply
  • Toss Out Cardboard And Paper
  • Wash All Recyclables
  • Store Pet Food In Air-Tight Bags
  • Seal All Holes And Cracks
  • Take Out Garbage
  • Eliminate Moisture
  • Use Cockroach Spray
  • Place Traps
  • Sprinkle Some Boric Acid
  • Spread Diatomaceous Earth Powder
  • Repel Them With Plants

Also, the garage is easy to access the food inside your house. I am sure you have more questions. So, continue reading to find the answer. In this article, I have explained everything in detail.

What Are The Signs Of Cockroach Infestation In My Garage?

It is easy to identify a cockroach problem before you actually see one. Cockroaches are intelligent. So, they will hide when you are inside the garage. But as soon as you leave, they come out of their hiding. So, the sooner you spot the signs, the faster you will get rid of them. Keep a watch for these signs of a cockroach infestation:

Cockroach Droppings

Cockroach Droppings

Cockroach droppings are the very first sign of their infestation. They leave behind a dust of tiny droppings which looks like coffee grounds or clusters of dark specs. These are usually one mm wide and vary in length. You will often find these near shelves or in cabinets. 

Cockroach Egg Cases

Cockroach Egg Cases

Cockroaches lay cases or capsules full of eggs, known as oocytes. These egg cases differ for each type of cockroach. But one thing similar is that all cockroaches lay the egg cases once they are comfortable in your garage. The size of one egg case is 8mm, which is one-fourth of an inch. So, you cannot easily spot them unless they are in clusters. 

Allergic Reaction

Are you sneezing and coughing more than frequently inside your garage? Chances are it’s not due to the dust alone. So, it is high time you inspect the garage thoroughly. Cockroaches contain allergens that they shed from their body in many forms.

These allergens are found in their outer skin, droppings, and egg cases. All of these will trigger allergic reactions in humans. Common symptoms are similar to low-grade flu. Allergens can also trigger asthma symptoms in many. 

Smears Marks

Cockroaches produce dark smear marks in places with high humidity levels. The cockroach smear marks are often red-brown or brownish streaks. They appear in the areas where the cockroaches have crawled. One might confuse them with food stains. But they are hard to get rid of. You can spot these smear marks commonly on the walls and floors.

Unpleasant Smell

Cockroach infestation causes an oily misty smell in the air. This smell comes from cockroach droppings. And taint the things in the area. The longer this infestation is, the more unpleasant smell will continue to grow, contaminating all the surfaces and walls. It might also cause a smelly odor in your car.

What Is The Best Way To Get Rid Of Roaches In The Garage?

The best way to get rid of cockroaches in the garage is to remove their food and water sources. Cockroaches are common in garages, especially during summer. The air inside the garage is hot and humid, ideal for them to nest and grow. Your garage also provides them with plenty of shelter and food.

 Cockroaches can eat anything from leftover crumbs to molding food. And even the wallpaper, old magazines, and cardboard boxes. They will get their water from the leaky faucet or pipe, sometimes from standing water. So, the best way is to clean, clean, and clean. 

After throwing out all the unnecessary stuff and giving it a thorough vacuum, check for water leakage. Removing all the water sources is essential. Even a small amount of water can increase the humidity of an enclosed space. So, ensure to keep water out of your garage. Then you can use gel baits, Boric acid, or any DIY roach killer you want. 

Should I Be Worried About Cockroaches In The Garage?

Yes, absolutely. You should be worried about the cockroaches in your garage. Cockroaches tend to make their colonies as soon as they find a place with shelter, food, and water. If you ignore their presence in the garage, there is a high chance that they will sneak inside your house. And their population will continue to grow. 

It is much harder to deal with a massive infestation than a few roaches in a small area. So, as soon as you spot a cockroach in your garage, dead or alive, be alert. It is time for you to search the entire area carefully for their entry points. Look out for their small colonies and nest in the cracks, crevices, near pipelines, shelves, and old furniture. 

What Causes Cockroach Infestation In Garage

Just like all other pests, cockroaches also look out for three things when they plan to nest. These three things are warmth, water, and food. The cockroaches will invade your garage when it provides them with all three things. Also, the garages are dark and secluded from the house. It has little to no human activity. Cockroaches are nocturnal and hate humans. 

They tend to stay away from human sight. Hence the garage is a perfect place for them to hide with no humans or light. Lack of cleanliness is one of the main reasons for cockroaches to nest inside the garage. People tend to keep their years-old things in garages. 

That can be old magazines, paper, cartons, and furniture. All of these are breeding grounds for bugs. The worst is when there is a leaky faucet or pipes. Also, some people keep their garbage bins near garage doors. Garbage is one of the leading causes of cockroach infestation. It will be worse if you don’t take out for days. 

Where Do Roaches Hide In The Garage?

Cockroaches hide in dark and humid areas. In the garage, they can hide inside cracks and crevices in walls, doors, and windows. The most common hiding places can be garbage bins and recyclables. The dirtiest places with food crumbs attract bugs more than anything else. 

The garbage cans that are not washed for days or years old household stuff, which you never even look back at after throwing out in the garage, are the main breeding point of cockroaches.

So, when searching for cockroach hiding places, inspect places with food and water supply nearby. Also, search through the ceilings and walls. Sometimes leaking water pipes inside walls can also cause cockroach invasion.

How Do I Keep My Garage Cockroach Free? 

The first line of defense against cockroaches is to outsmart them. It means keeping away all the things that they are attracted to. Cockroaches invade the garage for shelter, food, and water. So, the key is to figure out how to keep all these things out of your garage. Following are the ways in which you can do that.

Remove All The Food Sources

Cockroaches can feed on anything from rotten fruits and vegetables to food crumbs. So, clean the garage if you ever take food in there. Cockroaches can even eat things like toothpaste. Hence, avoid keeping any food-related items in your garage.

Stop The Water Supply

Cockroaches need water to survive. Garages are more likely to have leaky pipes or a dripping hose due to a lack of maintenance. This water leakage can cause puddles of water on the floor that will attract bugs. The leakage can also come from holes in the roof and improper roof drainage. So, inspect all the water pipes running through the garage. 

Toss Out Cardboard And Paper

Cardboard boxes, old newspapers, and magazines are breeding grounds for cockroaches. They provide them with bedding, nesting place, and even food. Cockroaches can even nibble on the paper when they are starving. So, throw away every paper item you have in your garage. Or you can keep the essential things in airtight containers.

Wash All Recyclables

Many people collect recyclable containers and bags to reduce plastic waste. But they forget to wash them before keeping them in storage. The food particles on the containers and recyclable bags will attract bugs. So, it is essential to wash recyclable items before storing them. And, also give them a thorough wash once in a while. Plus, ensure to dry them before keeping them back in storage. 

Store Pet Food In Air-Tight Bags

Cockroaches can eat anything, even pet food. If you have pet food lying around in your garage without a proper seal, chances are cockroaches are also feeding from it. So, to save your money and energy, keep all the pet food in large air-tight bags and containers. Also, make sure to clean these containers once in a while.

Seal All Holes And Cracks

Cockroaches are tiny. They can crawl inside garages from a hole as small as 2mm. Cracks and crevices in windows, doors, ceilings, and walls are easy to access. So, thoroughly inspect your garage exterior after every few months. If you find any hole, fill it with caulk or silicone and foam. 

Take Out Garbage

Garbage is one of the chief sources of pests. Any place with a heave of waste will attract cockroaches. It is dangerous to place garage bins in garages. The roaches living in that garbage can move inside your house. But your first step must be to clean out the garbage bin. And give it a good wash. Keeping the garbage bin clean is as important as clearing it out. 

Eliminate Moisture

Cockroaches prefer to live in an environment with 90 to 95% humidity. That is why you see them mostly during summer. Any water source in the garage can be the source of their infestation. Seepage on the walls can also increase the moisture level of closed spaces. Rain and snowfall also create humidity in the garage. So, keep the garage dry by installing heaters. And fix all the leakage issues. You can also lodge a drain for the rainwater. 

Use Cockroach Spray

Using cockroach sprays in the garage is frequently simple. These sprays contain chemicals that paralyze their nervous system. It might not kill cockroaches instantly and can take up to a few days. But the results are successful. After cleaning the garage, spray it with roach killer. So, any hidden roach can also die. You can also use foggers or bug bombs to eliminate them from invisible cracks in walls. 

Place Traps

Cockroach traps are a common way of controlling their infestation. There are many different types of cockroach traps available in the market. You can use adhesive traps or even gel baits. They work effectively against any cockroach size and can even clear out massive infestations.

Sprinkle Some Boric Acid

Boric acid is lethal for humans and animals. So, if you are using it in your garage, make sure children and pets cannot find their way to it. Boric acid causes severe dehydration in cockroaches causing a slow and painful death. Simply spread Boric acid powder on all floors, walls, and shelves. You can also make Boric Acid baits by mixing them with sugar and flour. 

Spread Diatomaceous Earth Powder

Diatomaceous Earth Powder is one of the oldest and most effective ways of eliminating bugs. It is a whitish powder with a crystalline texture of particles. It kills bugs by penetrating the skin causing water loss. Cockroaches die from severe dehydration. Unlike Boric acid, it is not lethal but can trigger respiratory issues. So, use a mask while spreading it in the garage.

Repel Them With Plants

To naturally repel cockroaches from your garage, grow plants that cockroaches hate in its surrounding. Cockroaches don’t like the smell of peppermint, garlic, eucalyptus, chrysanthemums, rosemary, catnip, and lavender. They also hate citrus fruits, chilies, and limes. So, growing these plants will give your house a fresh look and keep roaches away. 


Cockroaches can sneak inside your garage if it provides them with food, water, and shelter. It is also an ideal place for them to live in. Garages have high humidity levels and little to no human interference.

Cockroaches are nocturnal. So, they like dark places with no humans around. Inside your garage, they can hide in old books, papers, cardboard boxes, and recyclable containers. Garbage cans are also the main reason for cockroaches to save your garage.

They will get their food source from there. Any leaky pipes and hoses will provide them with water. So, if you want to keep roaches out of your garage, keeping it clean is a must. Then proceed to use pesticides. 


What To Do If You See Roaches In the Garage?

If you see a cockroach in the garage, spray it with pesticide. Your next step is to inspect the entire garage for roach infestation. Then clean out the area using a vacuum. Throw away all the extra things that no longer serve any purpose. If there is a garbage bin in your garage, move it somewhere else.

What Do Cockroaches Eat In The Garage?

Cockroaches can eat anything they find. They can feed on food crumbs, toothpaste, old books, magazines, cardboard boxes, and even pet food. They might also nibble on wallpaper if they cannot find anything to eat. Basically, anything that is not toxic is a food item for them. 

What Things Attract Cockroaches In The Garage?

Any place with food, water, and shelter attracts pests. Cockroaches hate brightness and humans. The garage, unlike other household parts, is less active. Also, there is almost no light in there. It makes their ideal place to live. Also, high humidity levels in the garage are perfect for breeding and nesting. 

Is It Common To Have Cockroaches In Garage?

It is not common to have cockroaches in the garage. But it is not impossible. So, if you have a cockroach infestation in your garage, there is no need to panic. All you have to do is give your garage a good clean. And figure out the cockroach access. Then, spray or spread pesticides in the entire garage. 


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Hassan Nasirian, Aref Salehzadeh, Control of Cockroaches (Blattaria) in Sewers: A Practical Approach Systematic Review, Journal of Medical Entomology, Volume 56, Issue 1, January 2019, Pages 181–191.