Despite the fact that this was a rather messy adventure (see pictures below), I would highly recommend both boric acid and diatomaceous earth for eradication of cockroaches. Granted, I don’t know how big of an infestation some people may have, however, ours was preettttyyyy bad…bad enough that at night when they came out (I assure you this was all before we were fully moved in) they were not afraid of me and were wandering all over the middle of the floors, at least 20 to a room that I could see. And anyone with a cockroach problem always knows that what you can see is usually just the tip of the iceberg.
I have not seen a live cockroach since we moved our stuff in. Granted, this has only been….six days, but that’s quite a while for as many as there were.
What I did was buy a bag of diatomaceous earth (safer brand for $8.97 a bag) and 2 bottles of boric acid (hot shot maxx attrax for $4.47 a bottle) from home depot. I used half of the bag of diatomaceous earth and one and a half of the bottles of boric acid.
The diatomaceous earth was the first to go down. Keep in mind our house was empty so the mess that this stuff can make wasn’t as big of a deal – it’s a big akin to dropping a load of powdered sugar all over your house in its consistency and fluffiness. You can spread it with your hands, but the way that it works is basically by dehydrating the cockroaches to death, so keep in mind it will make your skin pretty dry. It’s totally non-toxic, but can irritate the eyes since they need to stay moist and not get a drying agent in them – understandable. So be aware of that. We pretty much put this stuff along every baseboard in the house, heavily by the doors, cracks in the floor, and places where it’s obvious they could enter the house or where we had seen them before.
The boric acid can be toxic, so you either don’t want to leave it down for prolonged periods of time, keep it out of reach of children/pets, or make sure that you clean it up very well. I read about a mix that would help attrack the cockroaches to the boric acid mixing 4 parts boric acid, 2 parts flour, and 1 part cocoa powder. I mixed up a big batch of that and had it sitting in shallow dishes in almost every room prior to us moving in. After we started renovating, I moved this to out-of-reach places and behind appliances like the stove and fridge where they’re more likely to hide. At this point in the move (the moved in part) I have taken those containers and sprinkled them around the base of our house outside to kill any that are under the house or wandering around the perimeter of our place. Any other applications of the boric acid in the house was poofed into crevices and cracks that are not exposed to people, but are open to the walls or other weird hidey holes where they might be living. For instance, we have wooden floors and some of those boards are cracked in the room we haven’t refinished the floor in – I put some in there. Pretty sure it goes straight to the frame of the house/the dirt under the house, but if they’re there, I wanted them dead. There were some cracks in the walls. I poof that stuff in, and then we spackle/joint compound that section of wall to seal it up and paint over it.
The diatomaceous earth takes a while to clean up. First I swept, then I vacuumed (pretty sure it would clog a vacuum if you straight vacuumed half a bag of this up, even as powdery as it is), and then you’ll definitely have to mop to get the last remnants of the dust. Obviously this can be a bit time-consuming and a pain if you don’t have an empty house, but like I said, the roaches are gone. Also to note, you have to give this a little bit of time to work. I applied the diatomaceous earth at least a week and a half before we moved our stuff in and didn’t sweep it up until after we had moved everything in. Everything I’ve read says to give it at least 2 weeks to act, longer if you can afford to, but we didn’t really need longer since I quit seeing roaches.
I’m saving the bag for any future sightings, but I expect that they’ll be a long time off. A messy, slightly inconvenient solution, but one that has worked far better than spraying them when you see them with RAID, gassing yourself out of the house, or blowtorching them as you see them in the kitchen. Totally worth the big of mess and time it takes to clean it up.
Hope this helps at least one person with their least favorite part of Florida (besides the bad drivers and the humidity).
Gnarly Farms 
Were you able to find straight Boric Acid? I am in Tampa and all I can find is stuff with added unknown chemicals (if I wanted that I wouldn’t be looking for natural alternatives such as boric acid). My pup brought home a couple of fleas, and just the thought of them in house is driving me crazy!!
I bought pure boric acid for cheap on amazon.
Dollar General sells a large bottle of boric acid for about $1
I mixed boric acid and diatomaceous earth together in a 1:1 ratio. Got a pump powder dispenser, and liberally used it under the furniture and large appliances in my home (bed, couch, dishwasher, etc.) and the base boards. When I cleaned it, I pretty much left the dust under the furniture in place as a residual defense and never overly cleaned the cracks and crevices along the base board. The key was to leave residual amounts of the dust mix.
I did this over 2 years ago; I have not seen another roach, flea, ant, spider, tick, dust mite, bed bug etc. in other words, if it crawls, it will not survive.
Again, the key is to leave some ‘dust’ behind. Under your fridge, sink, dishwasher, couch are great places to leave some dust behind and will help prevent future infestations.
I have since fired my exterminator. This technique is THAT effective.
Do you have a cat or dog? I know that the diatomaceous earth is safe for pets, but not so the boric acid. Like you I thought I could combine them, i my instance for carpenter ants.
I do currently, but did not at the time of making this post. Another thing to try for ants is beneficial nematodes – that’s going to be my next attempt to help with general pests in the yard and to help the garden out.