Boric Acid (roach killer) safe to use in my cupboard?
June 23, 2006 6:49 AM   Subscribe

I'm Using Boric Acid for a cockroach problem - is it safe to put it in my cupboard next to plates and cups?

I don't have a huge roach problem but enough to make it a nuisance and me and my wife are pretty disgusted by them. I usually see about 1 or 2 a week in the kitchen only.

I've read this thread: and I'm using three different roach "killers". I layed down boric acid, Combat roach Gel and have put out Raid Roach traps. I don't know how long this stuff is supposed to take to work but it's been almost a month and we're still seeing them.

I purposely avoided my cupboards because I didn't want toxins near my plates and cups. Today however I saw a roach in my cupboard.

Is it really bad to put down boric acid in my cupboard? Obviously I'd wash any plates or cups before using.
posted by bingwah to Health & Fitness (18 answers total) 11 users marked this as a favorite
Try this recipe for getting Boric Acid around your dishes and hard-to-powder spots (like under your couch):

1 cup flour
1 small onion, chopped
6 oz Boric Acid
1/4 shortening (or a little less vegetable oil)

Blend until crumbly, and then add enough water to moisten. Make marble-sized balls. Put them everywhere.

I think this works better than plain BA because the roaches are much more likely to nibble away at it. Every time my friends and I have used this method, it's wiped out any roaches for months.
posted by lucyleaf at 6:56 AM on June 23, 2006 [2 favorites]

My mother uses Borax and sugar in a squeeze bottle (like a picnic ketchup bottle) to put lines down for them. If it really worries you, you could remove the dishes to a storage bin or something for a week or two.

I live in Texas where roaches are a fact of life. Right now, they are coming in looking for water, so we dry out the sink and bathtub and use the Borax/sugar mixture outside around the foundation, especially near water faucets and windows.
posted by Lyn Never at 7:12 AM on June 23, 2006

lucyleaf, your recipe says '1/4 shortenng'.... I'd love to try it, but I'd rather be clearer on my measurements first. :)
posted by Malor at 7:18 AM on June 23, 2006

Whoops! That should be 1/4 cup shortening.
posted by lucyleaf at 7:21 AM on June 23, 2006

Response by poster: Thanks for the advice. I also found this Boric Acid recipe from Heloise, which also calls for making balls of boric acid:

Maybe the "boric acid balls" technique is the way to go. I'll give it a try.
posted by bingwah at 7:23 AM on June 23, 2006

I believe boric acid itself isn't toxic, just extremely acidic. It's used in eye ointments (in low concentrations) and as a treatment for yeast infections.
posted by needs more cowbell at 7:51 AM on June 23, 2006

Whoops, wikipedia says it's actually a mild acid but you shouldn't inhale or eat it. But still, it's not toxic in the way that other bug sprays might be, it seems.
posted by needs more cowbell at 7:53 AM on June 23, 2006

How easily is Boric Acid cleaned? Is it safe to put in a blender then use the blender again for food purposes?
posted by kc0dxh at 8:00 AM on June 23, 2006

Response by poster: I would think if you clean the blender thoroughly it should be ok. Maybe even wipe it with rubbing alcohol.
posted by bingwah at 8:09 AM on June 23, 2006

I have a great deal of experience with boric acid. It's relatively benign, but, as another poster said, you don't exactly want to inhale, ingest, or snort it. The boric acid I used was exclusively a powder. It's not going to kill you if you eat a little bit. Just don't be silly with it.
posted by BioCSnerd at 8:28 AM on June 23, 2006

My mother uses Borax and sugar in a squeeze bottle (like a picnic ketchup bottle) to put lines down for them.
Add water, and that's basically what Terro is. According to the Terro FAQ, it's harmless to people and pets.
posted by MrMoonPie at 8:49 AM on June 23, 2006

Are the shortening/boric acid balls pet-safe?
posted by kimota at 9:24 AM on June 23, 2006

Oops. should've previewed. Thanks, MrMoonPie!
posted by kimota at 9:25 AM on June 23, 2006

Boric acid as a powder is fairly effective against cockroaches, but it takes anywhere from a month to 6 weeks in most cases to eliminate a nest. Generally, the powder sticks to the legs of adults, that pick it up foraging for food, and carry it back to the nest, where they ingest it when cleaning themselves. Adults who die in the nest will then be eaten by juveniles, thus passing the poison from the adult carcasses on to later generations. You may see a higher proportion of smaller (younger) insects after a week or two, indicating that this mechanism is working, and boric acid has been effectively transported to the nest. But you will not see the end of an infestation until the last hatchable eggs have grown into juveniles that are big enough to forage, and that have also been posioned and die. For German cockroaches which breed rapidly, and mature in 90 days, this process can cycle through in as little as 3 to 4 weeks, but for other slower growing species, such as common brown cockroaches that live up to 18 months, you may be in for a couple of months of decreasing levels of infestation. Keep your roach powder dry, and eliminate access to water and food.

Some of the better roach powders also contain silica aerogel powder, which works as a desiccant, and removes the waxy coating of the insect's carapace when the insect tries to clean itself. Death is hastened by dehydration of the insect's body. Some roach powders also contain diatomaceous earth powder, which consists of sharp, needle like silica crystals, that are thought to pierce the insect's exoskeleton, further contributing to dehydration, but which may also be ingested by other neophyte roaches scavenging adult bodies.
posted by paulsc at 10:28 AM on June 23, 2006

Response by poster: Tons of great info. It gets discouraging when you keep seeing them even though we're pretty clean and careful with food.

Not sure what type of roaches they are. I'm guessing German but I've not had a chance to get a good up close look at one. Next time I kill one I'll try and figure it out. They're not that big, less than an inch.

I've been seeing these miniscule bugs but I'm not sure if they're baby roaches or not. They are about the size of an ant (small brown ant, not the larger black ones) and have antennae like a roach. But do roaches that small forage for food? Maybe the Boric Acid is working.
posted by bingwah at 10:54 AM on June 23, 2006

Can I piggyback on this question to ask if boric acid will work on the bane of my existence, the house centipede?
posted by ereshkigal45 at 12:06 PM on June 23, 2006

ereshkigal45: Having house centipedes is a good thing. They eat all kinds of small insects (like cockroaches). However, given that a house centipede is an arthropod and has an exoskeleton, boric acid may work to kill them (as I understand it the boric acid works to break down the waxy layer on the outside of the exoskeleton causing the arthropod to dry out). This site suggests using boric acid as a control.

All that being said, I would urge you to reconsider adopting a new bane of your existence.
posted by gavia at 12:42 PM on June 23, 2006

I knew someone would tell me that they are beneficial, but try as I might I really can't get over the serious case of the wiggins they give me. And surely I don't need as many as I seem to have. I kill at least one a day in summer.
posted by ereshkigal45 at 12:53 PM on June 23, 2006

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