Diatomaceous Earth (food grade): bug killer you can eat!

what the heck is it?

diatomaceous earth warrior

Diatomaceous Earth (often referred to as "DE") is an off white talc-like powder that is the fossilized remains of marine phytoplankton. When sprinkled on a bug that has an exoskeleton (such as bed bugs, ants or fleas) it compromises their waxy coating so that their innards turn into teeny tiny bug jerky. But it doesn't hurt mammals. We can eat it. We do eat it! It's in lots of grain based foods because lots of grains are stored with diatomaceous earth to keep the bugs from eating the grain!

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Die bugs! Die! Die! Die!

I have heard two explanations of how diatomaceous earth works.

diatomaceous earth magnified

One is that on a microscopic level, the diatomaceous earth particles are very sharp looking. These particles stick to an insect and get stuck between its exoskeleton joints. As the insect moves, it gets physically cut up.

The other explanation is that diatomaceous earth sticks to the insect and somehow causes them to dry out. I think this approach involves scratching the insects waxy layer which then allows precious moisture within the insect to get out. So their teeny tiny bug-innards turn into teeny tiny bug-innards-jerky.

A reader, Sue, in Washington state writes:

Both are true and connected. DE is almost pure silica (with some beneficial trace minerals); under a microscope, it looks like shards of glass (glass is made from silica). On any beetle-type insect that has a carapace, like fleas and cockroaches, the DE works under the shell and punctures the body, which then dehydrates and the insect dies. DE is totally nontoxic. There is no buildup of tolerance like there is to poisons because the method of killing is PHYSICAL, not chemical.

bug running from diatomaceous earth

The important thing to us is that if an insect with an exoskeleton gets diatomaceous earth on them, they die. At the same time, we can rub it all over our skin, rub it in our hair, eat it .... whatever ... and we are unharmed.

Diatomaceous earth kills all bugs. It has been reported to be the most effective solution when fighting pests like fleas, ants and bed bugs.

Farmers dump food grade diatomaceous earth by big scoops in with grains when the grains are stored. It kills the insects that want to feast on the grain. This is a great improvement over the stuff they used to put in with the grain.

Farmers feed gobs of diatomaceous earth (food grade) to animals in the hopes that it will cure whatever ails them. Many farmers swear that the stuff kills all sorts of worms in their critters.

Many people eat a quarter cup of food grade diatomaceous earth every day. They mix it into juice. I have visited with several people that are keen on living past 100 years that believe that eating lots diatomaceous earth every day will help them with that goal. I have found references where it is cited for colon cleansing, parasite control and detox.

diatomaceous earth fighting ants on an apple tree

One strange thing about diatomaceous earth is that for it to work on killing bugs, you have to keep it dry. Even morning dew can make diatomaceous earth ineffective.

I have encountered over a dozen ignorant boobs that have proclaimed "Diatomaceous Earth does NOT work!" I have read this statement in all caps. In extra big fonts. With italics. And I've even had it screamed at me. I'm gonna stick with "ignorant boobs". On closer inspection of each case there is always a flaw. Usually the problem is that it was not used correctly. Diatomaceous earth is not a bait. If you put a little bit in a pile somewhere, the bugs are not drawn to it and invite all their friends. I kinda wonder if the pesticide companies pay people to go to internet forums and say this sort of thing. Diatomaceous earth is super cheap, non toxic, and generally more effective than anything the pesticide companies have to offer - so it kinda cuts into their profit margins a bit. I've been meaning to create an experiment to set the record straight on this topic, but a participant in the diatomaceous earth discussion, Stephanie, beat me to it:

I tried my own experiment with the diatomaceous earth to see how quickly it kills the fleas; I caught a few fleas and put them in a jar with a pinch of diatomaceous earth - all were dead within just a couple of hours.

It just doesn't get any more clear than that.

How safe is diatomaceous earth?

The only known problem for people, mammals and birds that I have ever been able to find any reference to is breathing it in. For food grade diatomaceous earth, there is only the bother of breathing in any dust. There exists another variety of diatomaceous earth that has been fiddled with so it can be used for pool filters. The pool grade stuff would be bad for you because it contains up to 70% "crystalline silica". My understanding is that if you work with the pool grade stuff all day, every day, for years, you could get cancer. Don't mess with the pool grade stuff. Food grade diatomaceous earth will contain less than 1% crystalline silica.

This article is really about the pure, food grade diatomaceous earth. I have to say "food grade" over and over or some nitwit will quote a small slice and then bring up the pool grade issues.

I have heard from two people that said that they won't use diatomaceous earth anymore because "the tiny particles cut my lungs!" --- (deep sigh goes here) All I can say is "Did you actually examine your lung with a microscope and watch the diatomaceous earth cut into it?" - of course, they did not. I think the truth behind these reports is that these folks heard how diatomaceous earth works, and when they would breathe in the dust, it would make them cough - just as breathing in flour or corn starch would make you cough. And then they thought of the sharpness at a microscopic level. My understanding is that when diatomaceous earth becomes moist, the sharp thing is no longer happening. That's why you have to keep it dry when you use it.

diatomaceous earth and flour

I have heard that people working in the diatomaceous earth (food grade) mines have no greater health problems than the people working in any other mines. (I would like to get some sources for this info - if anybody has a link, please email me)

As long as you are using food grade diatomaceous earth, you are perfectly safe. Even if you breathe in gobs of it. Of course, if you are asthmatic or have lung problems of any kind, I would think breathing in big gobs of any kind of dust would be a bad idea.

gimme gimme gimme!

There are a lot of varieties of diatomaceous earth, so when you are shopping, be sure to get the right stuff!

Make sure that you get food grade diatomaceous earth. Some people make 3% of the food they eat be diatomaceous earth. There are claims at parasite control, longevity and all sorts of perks. I know that food grade diatomaceous earth is used heavily in storing grains - so you are probably already eating lots of diatomaceous earth every time you eat any bread, pasta or other grain based food.

Farmers feed food grade diatomaceous earth to their animals to reduce parasites and provide other benefits.

Some places sell the diatomaceous earth (food grade) mixed with other stuff. And that is something I do not recommend. When I see a label that says "97% diatomaceous earth" I have to wonder what the other 3% is. If the packaging is about killing bugs, is it some sort of toxin? Did they add something like borates or pyrethrin for a little extra kick? I don't want that!

Some places sell diatomaceous earth that is for swimming pool filters - that is definitely what you do NOT want.

Some places sell an 8 ounce shaker. I think it is wise to get at least a few pounds of the stuff. It keeps well (it's already millions of years old) and is useful for so many things. And if you get too little, you are likely to not use enough.

So I've done a lot of research on this .... and I've used diatomaceous earth from about eight different sources ... and here is what I'm recommending: This is food grade diatomateous earth tht is less than 0.5% crystaline silica - a lot lower than the 1% to 3% for most food grade diatomaceous earth.

diatomaceous earth from a box diatomaceous earth from a bag diatomaceous earth from a sack
  • Diatomaceous Earth (food grade) - Five Pounds
  • Diatomaceous Earth (food grade) - Ten Pounds
  • Diatomaceous Earth (food grade) - Fifty Pounds
  • for those in Europe, here is some amazon.co.uk links:

    diatomaceous earth in a bucket
  • Diatomaceous Earth (food grade) - 1kg
  • Diatomaceous Earth (food grade) - 4kg
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    Now, how do you sign up? Just fill up the form below:

    Wilbur the Calf

    This space was blank and rather than take the time to fix the page so it wasn't blank, I just added this picture of wilbur the calf.

    Looky! A whole book on diatomaceous earth!

    diatomaceous earth (food grade) book

    So the author sends me an email about the book and I say "If you comp me a copy I might mention it on my DE web page." And the book arrives in my mail! So for months it sits on my desk. And when I finally read it: it is exceptionally good! Well researched and, my favorite part, the information is well qualified: anecdotal information is labeled as anecdotal. Research data is labeled as researched. Nothing is presented as absolute fact unless it really is absolute fact. The book explains stuff I didn't know, like how it works to control parasites in mammals. The book also covers how diatomaceous earth is used for cleaning and personal hygiene. A big thumbs up!

    The diatomaceous earth book at amazon.com and at amazon.co.uk.

    More about the diatomaceous earth book from the author.

    Bonus pics!

    A reader, A. C. Bryant, wrote to me and said that she is has spent time as a scientist studying diatoms! She then sent me a bunch of info and pics to paste on this page:

    Most of these are dead because I mixed them with acid to remove the organics before I cleaned them and mounted them permanently on slides. When they die, most of them will come apart so most of these are views of half of the shell. The tendency is for them to lay flat as they settle and this gives us a great view for identification. Most of these I'm naming from memory so may not be entirely accurate as to species but are pretty positive for genus. Measurements are in microns.

    (click on an image to see it in freaky big size)

    A. C. Bryant collecting a benthic sample. Triceratium reticulum - 46.4 microns per side Triceratium favus - 163.6 microns per side - of note is how large this is, and it is large! As a freshwater diatom, it tends toward a larger size with a robust shell. The background shows a very typical litter field of broken shells, basically the same thing diatomaceous earth comes from. A couple of Surirella species on a background of general diatom litter. Note the small complete one between the two large ones, and a small entire round one at 10 o'oclock of the upper large one. The brightness is from the astounding level of reflection these silica shells have, just like a field of broken glass. This is a Podosira species. The rough area where there are no pores is the connection point. Note that it is off center. These Podosira connect in chains that curve as they don't connect directly center to center. Until naming conventions had restrictions, people who discovered them could name them anything using whatever inspiration that came up...merely latinized most of the time. This one has a non-nasty name, but not all of them have been renamed. Opephora swartzii - 105.4 microns - Another large one that shows the detail of it being cupped and showing the openings in the shell and thin spots. One of my personal favorites, this is Navicula lyra. Easy to see how it got its name. Another Navicula species with the reflections minimized to see the gorgous details. Cyclotella species, probably stylorum - 39.3 microns - There is one half of the interior portion well in focus, the other half focuses at a different plane, showing it has a wave like profile as well as being round and petri dish like. This Coscinodiscus species is only 71.4 microns in diameter, yet clearly shows how wonderfully complex they are. Petri dish style connection with hundreds of individual depressions to gain what it needs from the outside. And with all that complexity, it is pizza pie in divisions also. A Coccneis species on a texture field of broken and partial diatoms. The Caloneis species shows the reflection properties of the diatom shell. Beautiful. Here a Biddulphia didn't come apart after death and during mounting, giving a sideways view of this small diatom and the way the shell halves fit together. This Bacteriastrum is a bit out of focus, but shows that diatoms come in the most bizarre shapes. And finally, this Auliscus possibly caelatus, diatom shows that they can look like a science fiction alien designer's finest creation. And all in a 45 micron long piece of living art, less than the average diameter of a human hair. Imagine...

    These images are all copyright © A. C. Bryant

    All these photos were taken under a light microscope, a zeiss, with a microscope mounted camera. Some are in black and white in order to bring out shadows needed for something specific. Most are in color and the amazing colors you're seeing are because the light reflects on them much like glass. They are very similar.

    If you note in the photos you can see how they are cupped to accept their other half. They tend to fit together with each half of the shell much like a petri dish, one side slightly larger than the other, with the organic elements set safely inside. They reproduce multiple ways, via division, auxospore or even sexually to regain size, as they get smaller with each division.

    And as a side note, Diatoms make up about 98% of the phytoplankton out there, and about 60% (or more) of the oxygen in the world. They are as essential to our life as our own hearts.

    DE is just very old, or sometimes not so old, dried out Diatoms shells. They are primarily silica, which means that they act like glass in many respects. They don't react with many other compounds, degrade very slowly, are brittle and sharp and largely inert. While this makes them chemically invisible to people and animals and kills via physical...or rather mechanical...means, via cutting, it also works as inert material within the gut, filling it up with something they can't process and blocking further feeding or digesting.

    For more information on diatomaceous earth, and to talk with folks about diatomaceous earth, visit our forum thread on diatomaceous earth!