Killing Roaches Part 3… Eradicating Roach Colonies With Diatomaceous Earth
BREAKING NEWS:
I have edited everything I previously wrote about eradicating cockroaches (along with some new research) and published it as a FREE online book.
Now, instead of piecing together my advice from the posts and comments on this blog, you can read everything you need to know in one place – a step-by-step plan is included. I call it the “Cockroach Assassin Report.” The book has been published as a stand-alone website with a table of contents and the full text. A print edition is available for people who prefer a physical book over digital books.
Read this Special Report at:
www.CockroachAssassin.com
In my earlier posts about my roach killing expedition, I mentioned my discovery of Diatomaceous Earth. This non-toxic powder has the ability to kill roaches (and a whole bunch of other things) without poisoning them. It is microscopically abrasive and cuts and scratches the roaches inside and out. Since it’s not a poison, it doesn’t lose potency over time. So, one good application will last a long time.
NOTE: Only use food grade diatomaceous earth or a product specifically labeled for pest control. The type of diatomaceous earth used for swimming pool filtration SHOULD NOT BE USED!
With a baby in the house, I was looking for non-toxic options for long-term use. This seemed like a very good product, so I started to hunt around for a local supplier. In New York City this wasn’t readily available (I didn’t have time to search around at gardening centers) so I ended up ordering it from Amazon. They also had a mint oil based non-toxic spray, so I got a couple cans of that as well.
When my 4 pound bag of Diatomaceous Earth arrived from Amazon I immediately set out to using it. I discovered a few things about how to best use Diatomaceous Earth in your roach killing efforts.
The first important thing to note is that, while Diatomaceous Earth is not poisonous to humans, it IS an irritant. It will get on your skin and dry it out like a mudpack. It has a mild, but noticeable, odor and it can irritate your eyes.
The second important thing to note is that Diatomaceous Earth will easily disperse in the air and form a cloud of fine particles that hang there a long time and then settle on everything in the room. This is not necessarily a bad thing!
Where To Apply Diatomaceous Earth For Effective Roach Killing
The goal with a product like Diatomaceous Earth is to get the roaches to track it back into the walls where it kills the roaches in the nest. A common application is to dust it under sink cabinets, stoves, refrigerators, and along baseboards. It is also good to spread it around outside if the roaches are coming from there (the powder in an outdoor application needs to be re-applied after rain.) I wanted to be even more aggressive.
If individual roaches tracking the Diatomaceous Earth into the walls was a good thing, I reasoned that coating the interiors of the wall with the powder would be even better – like a giant roach roadblock in the wall. I decided to drill small holes in the space between the wall studs in my kitchen and bathroom and blow the Diatomaceous Earth inside to coat the interior surfaces. A little drywall patching and paint afterward and I could relax in my own home instead of constantly scanning for roaches.
Applying Diatomaceous Earth For Roach Control
I got a plastic bottle with a cone shaped tip like those used for Boric Acid. Once filled with Diatomaceous Earth, I set out to dust under the refridgerator, stove, and along the baseboards in the kitchen. I tipped the bottle and squeezed it quickly to ‘puff out’ a little powder.
I was concerned early on that the Diatomaceous Earth would clog up the bottle, but the fine powder dispersed nicely. However, I got a little aggressive trying to blow the powder back under the fridge and, when I looked up, I noticed the cloud of dust hovering in the kitchen.
Blowing the dust inside the walls turned out to be a much easier task than originally anticipated. Only a small hole was needed to get the Diatomaceous Earth inside and some vigorous work with the bottle created a cloud of dust inside the walls which coated every surface with roach killing powder – sweet!
IMPORTANT NOTE: Wear a mask when applying Diatomaceous Earth.
One nice thing is that the dust clings easily to many surfaces. So, the sides of the stove and lower cabinets are now roach death traps. In fact, the vast majority of the kitchen surfaces are now inhospitable to roaches.
I was pleased to discover that the following day the number of roaches spotted in the kitchen had declined noticeably. And, I saw a couple of them moving slowly with a coating of the Diatomaceous Earth on their bodies. I found a few more in the glue traps around the kitchen coated in dust.
Unfortunately, new horror kicked in when I realized the roaches were moving into the living room looking for new hunting grounds. The bedrooms were sure to follow. This was not good.
New glue traps were quickly placed in the major roach pathways in the living room and Diatomaceous Earth was dusted under some of the larger furniture and along some of the hidden baseboards to keep the roaches contained.
The second day after applying the Diatomaceous Earth, we had almost no roaches in the kitchen at all. I did the usually rattling of dishes and opening of cabinets designed to flush the roaches out of hiding and found nothing. This was all the more shocking given the fact that I had fallen asleep leaving dishes in the sink and before taking out the very full trash. While washing the dishes, one lonely baby roach came out of hiding and I quickly dispatched him with a shot of my mint oil spray!
If you have any tips or special techniques for killing roaches using Diatomaceous Earth, leave a comment below and let everyone know!
The Go-To Guy!
Jeff,
I used each in sequence and did not mix them beforehand.
Boric acid works as both an abrasive (like DE) and a stomach poison. There is significant overlap as far as what they do to control pest, so you would be fine to use either one by itself. I liked the way the DE dispersed and clung to surfaces and wanted the extra stomach poison aspect of the boric acid too.
Good luck,
Andrew
I just purchased some DE to use around my mobile home. After a neighbor moved a trailer from next door to us, we became INFESTED….beyond infested. We’ve had multiple sprayings, bombed a few times….nothing has worked. Also, my elderly mother lives with me as well as a few pets and I didn’t like the idea of all those chemicals in the house. I started researching alternate Ideas. I haven’t tried the tobasco or the herbs yet but I’m going to, but I have started today with the DE. Unfortunately, as much as it needs it, I cannot plug our caulk holes and cracks….I live in an old mobile home that is older than I am….it is one of those places that needs LOTS of work, things like small holes are nothing. I have huge holes such as the bottoms of cabinets rotted out, etc. I don’t have the funds to fix them myself and my landlord won’t. I am going to have to hope I can control them when they come in, and your extensive article reassures me that at least I didn’t waste my money on DE 😀
Jeff,
Great info altogether, been reading up along the net for all kinds of ideas and like what I read here. Now to my dilemma…
Former Cali resident with no roach problems I couldn’t handle, now in Texas where I’m just grasping the issues of roach infestations in a desert environment. House is mainly sealed up externally Looking at sealing internally as well (not there yet). Problem is not an internal issue rather an external one. I have no nesting internal and house is sterile at all times, garage too. At night they come out of the desert sands and migrate towards the house and find ways in. Previously, pesticides have been used externally and roaches that do make it in die that same evening, close to where they enter.
I’m looking at using DE from here on out and I’m an ex-pool service technician. I know DE very well as a filter additive and how dangerous it is. Question is while searching across the net I feel I’m reading crossed messages. While I understand the importance of using food grade DE indoors, I don’t understand why pool grade couldn’t be used outdoors?
My reasoning, I don’t have a garden or pets outside and from reading DE differences, pool grade has a greater percentage of silica than food grade(i.e. 2% vs. 60%). Now if the silica is cause of the irritant, wouldn’t a higher percentage be better for eradication? I’ve read elsewhere that pool grade DE does not affect roaches, but I can’t see how that’s possible. I guess the only thing that would occur is that they would die quicker?
Just curious since I can purchase pool grade much cheaper the food grade if I plan on using it in desert sands. I mean really, would you pour food grade DE out in the desert (:
Thanks in advance
Hi,
I just discovered a roach in my bathroom last night–I’ve lived all over the US and I’ve never experienced this. I’ve lived in this apartment for 7 years and this is the first time I’ve ever seen anything like it. I mean, when everyone else was getting infested with stink bugs we had nothing at all. It was crazy.
When I first saw it I wasn’t sure what it was. It was about an inch long. Not sure what kind of roach that would be. Probably American?
Anyway, I literally went into panic mode, which was made worse when my teenager came home around 1 am and said there was one downstairs in the hallway. I grabbed my car keys and ran to Walmart and got DE. I should have grabbed some clear caulking but my mind was so focused on creepy crawlies that I never thought of it. I didn’t sleep at all. I’m pretty meticulous about being clean, but I totally emptied out my kitchen, pulled out the stove and refrigerator, and poured the stuff right into every single crack I could find. There are still some large holes under the sink and behind the stove, but I used Gorilla Tape as a temporary stopgap till I can call the building manager on Monday. Why do these things always happen on a weekend???
This morning, I went into hallway armed with the DE and a measuring cup. Not even a spray bottle. I sprinkled it all along the walls and baseboards and even on the steps. Later this afternoon I’m going down to the basement, which is a big wide open area, and I’m going to treat that, too.
And then we’ll see what happens on Monday when I call them.
DE is the same stuff they use in flea and tick powder for pets. I have two cats, and the way I see it is if they accidentally get any on themselves, well, it’s a two for one deal! Kill the fleas and ticks, too. Actually, my one cat is how I found the roach. She’s an indoor cat, so since she can’t hunt rodents she hunts bugs. She’s given me decapitated spiders as “presents”. Well, she went right after this thing and terrorized it till it found whatever absurdly small hole it went into.
I’m trying to figure out where they’re coming from, but my best guess is that they’re in the basement. There was a sewage issue about 6 weeks ago and if they didn’t take care of that properly (knowing them, probably not), well there ya go. It may just be a coincidence, but one of my neighbors just moved out as well and they were not the cleanest people in the world. They have not been back to clean their apartment and they’ve been gone for almost a month. I heard that they paid an extra month’s rent so they have till the end of July.
The first place to check for entry points is water and drain pipe penetrations in the walls. Common construction practice is to cut the holes a little big and put a trim cover around the pipe to cover the gap. These covers are not sealed and leave plenty of space for roaches to enter and exit the wall. They can travel along the water pipes through the holes drilled in the framing. I recommend using spray foam insulation to fill the gaps (and you might dust a little DE in the wall before you seal it up.
Apartments are tough. Your neighbors have a huge influence over the pest population. When someone moves out, pests go looking for a new food and water source. Any gaps in a shared wall can create an entry point. So, sealing gaps and cracks is a good first step.
I am trying to figure out if there is a safe way to use DE to get roaches out of the microwave
I wouldn’t recommend dusting DE inside a microwave. It will mess up the motors and the cooling fans will blow it around every time you turn on the microwave.
If they are inside the electronics, you will probably need to open it up to clear them out. If the microwave is mounted over the stove, you’ll have to take it down. If you are not comfortable around electronics, or have trouble lifting and moving things, enlist help.
Hi Andrew, so glad I found this page! I have only seen one live roach(which was caught in spider web in garage) but am finding droppings, similiar to mice droppings (only smaller) on bath towels. The towels are in an open rack… I have set traps for mice thinking that may be problem, only to find peanut butter gone in the morning with trap still set. So my question is if its normal to see the droppings & no roaches? Also found them(droppings) in a few drawers which I emptied & cleaned, then put roach bait & glue trap inside but of course no activity there. Im wondering if theres another critter or bug around or are the roaches hiding well? Thanks!!
Thanks for this post, Andrew. My girlfriend has similar roach problems and after several attempts bug bombing her place (which I was highly opposed to) I convinced her to give DE a try. I’ll let you know how it goes, but we’re just starting this war on those little vermon.
Thank you for the info about DE. We have an asthmatic in the house…do you think if I apply it around the house while he is out for a few hours, that it will bother him?
I’m a pest controller in London and have a problem with American cockroaches infesting kitchen drain sumps. We need to avoid contaminating the drainage water system with our usual range of insecticides ( stated on the label ) so I was thinking about DE applied beneath the drain covers and down the sides above the drain . We don’t want to excite the adults into movement to other more obvious areas and it’s hard work lifting the covers so we don’t often have access . Any ideas please ?
Once the DE settles, you shouldn’t have problems. Just make sure to avoid applying it to areas where there will be air disturbance. Avoid air vents, etc. so that you don’t stir up the DE after it has settled in place.
DE is not going to be a good solution for wet areas. The moisture will cause the dust to cake and then it will not stick to the roaches as they walk over it.
I have not encountered a directly similar situation, so I do not have a specific recommendation. You will likely have better results devising a bait trap that will adhere to the underside of the drain covers and deliver a conventional insecticide.
I found a large watercolor brush I have works great for dusting DE in kitchen cabinets, shelves, around stove etc., since I didn’t have a garden duster.
Laurel, that’s a good idea. I’ll bet one of those big makeup brushes for applying loose powder would work just as well.
Andrew
Thanks for the tips,I didn’t believe my husband when he said that DE works. Just now realizing we have a bigger problem than I first thought of I thought it wasn’t killing them fast enough but realize that they just keep hatching will continue to use DE. My landlord also will not treat any bugs we are in a drought and now I know they are looking for food and water!!! Thanks again
Cynthia,
Happy to help. Look into using hydroprene to slow down the reproduction process and help you get ahead of the problem. There is a section on the CockroachAssassin.com site that explains what it is and how it works. Check that out here: http://www.cockroachassassin.com/a-little-cockroach-birth-control.html
How long does it take to kill the roaches?
And thanks I found this really helpful.
Bill
Washington DC
Bill,
I started to see results in 24 hours, but it took several weeks to get at the roaches back in the walls and seal up all the cracks and crevices they were moving through. I was at a disadvantage because I had no control over the source of the problem (the woman living in the apartment above me.) But, I was able to get things under control without bombing the apartment in a steady bath of poison.
One thing I learned along the way is the importance of making my apartment inhospitable to roaches and maintaining it that way. Roaches can hitch a ride in boxes, bags, clothing, etc. and find their way into your home. The key is to make sure they don’t stay.
Andrew
Hello
How often do you have to reapply???
You shouldn’t need to reapply at all unless the diatomaceous earth powder gets wet and stops being powdery or the powder is removed. Since DE works mechanically to kill the roaches, it does not lose potency over time.
Hello….my son came to visit from texas, where his apartment had roaches, German I think. His bus trip was from Thursday thru monday, so I didn’t think I needed to be concerned. I washed all his clothes yesterday, but then I saw one of those little jerks several feet outside the bedroom he is in. I made him take everything I hadn’t washed outside in a bag. Unfortunately I live in an old manufactured home, and the water heater is in the closet in his room and I’m also dealing with mice (double yuck). So I need DE, to fill up the same holes the darn mice are coming thru, I’m a clean freak, so after I dust the DE, how long til I can vacuum, should I dump some in the holes before they are sealed, and then what else can I do? I bleached like my hole kitchen, and I know there’s never just one, even tho this one looked like a juvenile. I’m freaking out!!!!!
First, take a few deep breathes. I freaked out myself, but you can manage this. Definitely put some DE in the holes before plugging them up. I find places to leave DE behind furniture, appliances, etc. I recommend leaving some dusted around the baseboards in the closet with the water heater. Heat and moisture are two major things that roaches are attracted to.
DE works best in those hidden areas. The rest you can vacuum up.
Your goal should be to make your home inhospitable so that when the odd roach shows up, it doesn’t get a chance to get established.
You might want to put a few glue traps around the house as well. They will catch mice and roaches.
Good luck,
Andrew
Will it still work if you mix it with water?
No. Diatomaceous earth must be powdered to work as a roach killer. If it gets wet, the DE powder will stick together in a lump and then will not cling to the roaches as they walk through it.
Andrew
Thank you for this article. Will the DE mess up my vacuum? I’ve heard some reports of that.
Stacy,
I’ve never had a problem with DE damaging my vacuum. Once you’ve dusted it into place, you should leave it alone, and you don’t need to lay down a super thick layer. So, the chances of you vacuuming up enough of the powder to damage the vacuum seems remote.
Andrew
I moved into an apartment that had sat empty for about a month or maybe a little over. She was messy, had not reported a leak under the kitchen sink, and left many of the windows open. The apartment has been very buggy. I thought I saw a roach in the kitchen and in the tub. The landlord sent someone out to spray and most of the bugs I have found were beetles but I do believe that the bugs I am seeing in the bathroom are a type of roach. I had no bugs before moving in and no one else in the building has seen anything. My friend lives in the apartment below me and she has seen nothing. All the bugs I am seeing are tiny. They have to be young. I have been leaving DE in the tub and bathroom floor and I have only seen 1 dead bug in the last week and one small bug that randomly was in my bedroom (which I had seen no bugs). I am not sure how to move forward. The landlord seems very happy to get things sprayed and helping how he can but he is not sure how to handle this. I also don’t understand why the person below me isn’t seeing anything. Any help or advice would be great!
If the bugs entered the building through the windows of your apartment, they may not have migrated very far in the building which would explain why others haven’t complained – yet!
I would start by making sure all of the gaps and cracks around water pipes are sealed. Water is a critical resource that attracts roaches and gaps around water pipes provide a common pathway for the bugs to travel in walls. Most water pipes and drain pipes will have some kind of collar that covers the hole in te wall. But, if you slide it back, there is usually a pretty large gap around the pipe itself. This provides plenty of room for roaches to move. Use expanding foam and/or caulk to fill them in.
Andrew
Hi Andrew,
Thanks for sharing your experience. My husband and I have just moved to our new place in Toronto and the same thing happened to you, your wife and your daughter is happening to us. I was so depressed because of these nasty insects since we’re giving our best cleaning and re-cleaning everything, but I have to confess that when I found one of them this morning in our bathroom I had decided to leave the apartment. It is so mentally stressful that I told my husband that I wanted to move… but now, because of your book, I’m hopeful. If you were successful in your journey I can also be. I can be a hero and become a cockroach assassin.
By the way, how long did it take to get rid of these gross insects?
Thanks again!
Renata,
I’m sorry to hear you are having a similar problem (it is extremely stressful.)
If you put the time into sealing up cracks and crevices, you will experience a dramatic reduction in activity almost overnight (if they can’t get out of the walls you won’t see them in the house.) I highly recommend using glue traps to help identify where they are coming from to make sure you find all the cracks and gaps in the walls.
In total it took about 3 months before I felt confident to declare victory, the the bug sightings became much less frequent after a couple weeks. I was experimenting as I went, so your results will come faster.
I put the chapter on roach repellents in the book because peace of mind is critically important when living with the stress of an infestation. Put those suggestions to use – they help!
Best of luck, Andrew!
I work as a mental health clinician to a variety of clients. They ride in my car. I swear I saw a small roach scurrying across my floor . Will Be work in my car. I’m freaking out and want results fast. Will I have to reapply? Should I leave it down for 24 hours before vacuuming? Please help I’m losing my mind.
I don’t know if DE will be the best option for a vehicle. You can certainly spread it around and then vacuum it out, but it won’t offer any benefits after you vacuum up the powder. Cars are tricky because there are so many nooks and crannies to deal with. If it were my vehicle, I would probably start by cleaning it out as much as possible and giving it a thorough vacuum. Then, I would use a commercial pesticide to treat the carpets – specially under the seats where food crumbs often fall.
If you cannot use a traditional pesticide, plan to leave some of the DE powder under the seats where the bugs can track through it.
Good luck, Andrew!
Andrew
Thanks so much for this info. I’m happy to hear that the total erradication may take some time. I was absolutely panicking after seeing one, because my home has been pest free and clean for 18+ years, so I really did not know how to deal with the issue. Can’t afford to call in a professional service. I have a disabled child , and three pets so I really didn’t want anything too invasive. You’re expertise and the comments from others was enlightening. I’m using DE and Boric Acid and a commercial pesticide ( HD by O) in a cycle. Is this too much?
Jane,
Your approach sounds very reasonable to me. The DE and boric acid are good long term treatments that only need reapplication if they get wet, so I recommend keeping them continually applied in any places where a new infiltration is likely to occur. Glue traps are also helpful to tuck away behind furniture and under beds, etc.
In my current home I don’t have worries about infestations in the walls, so my main concern is preventing critters from getting into the house in the first place. The main points of entry are 2 exterior doors and windows. So, I use a barrier spray on the exterior of the house around the windows and doors. This means I use small amounts of spray, keep it outside of the living space, and the bugs can’t get in without exposing themselves to the treatment.
Andrew