The reason why I had that thought process, was that I know that powdered DE is included in livestock feed (and for cats and dogs) to remove parasites from the gut. I assumed a similar action could occur for earthworms but I am happy to be incorrect and better educated!
Edit: I didn’t think any graingers were around the burgh, but there is one in town and by the airport. Thanks!
One last thing the dust is not a good thing, work outside use that N95 mask, wet the product first.
Avoid breathing the dust, once wet it will never dust up again.
Interesting… and I’m tempted to buy a bag of OptiSorb to add to some new raised beds we’re putting in.
I’d been waiting for the ‘dewormer’ claim to rear it’s head.
DE has never killed a worm in an animal’s intestinal tract. Ever.
I know the ‘idea’ behind it… tiny little ‘razor blades’ that lacerate the worm’s cuticle, and they die of dessication. That might work if you put worms between two boards, sprinkled them with DE and rubbed the boards together. But… those worms are in a fluid environment in the lumen of the animal’s intestinal tract… imagine a few razor blades floating slowly by while you are soaking in the pool… they’re probably just going to ‘bounce off’ and float right on by… but on the off-chance that one did nick you… you’re in the water… you’re not going to dehydrate and die.
It’s a claim that’s been put forward, mainly by folks who are marketing food-grade DE… and grasped at, desperately, by ‘organic’ livestock producers… especially goat/sheep folks, whose flocks are frequently devastated by nematode parasites, particularly Haemonchus contortus, the ‘barberpole’ worm. Anecdotal reports of miraculous results of DE always tout things like brighter eyes, shinier coats, animals able to run faster and jump higher… very subjective, at best, bogus at worst. But if you look at fecal egg counts or hematocrit levels… DE does nothing beyond its benefit as something of a mineral supplement.
Scientific trials have shown that, at best, if incorporated into diet at a level of 5% or so…which in and of itself requires some major gyrations to get animals to actually eat that dry, dusty feed(like lots of molasses, oil, gravy, etc.)… it may cause feces to be dry enough that, for worm species that hatch out in the manure pats, larval survival may be diminished. If we’re talking species like dog/cat roundworms, whose eggs are extremely resilient and can survive for years in the environment… DE does nothing.
Now… I will concede that it may have some activity against external parasites, such as fleas, lice, etc.
OK. Stepping down off my veterinary parasitologist soapbox, now.
Tha NAPA product is Floordry. It can be bought at many stores even some Walmarts. I buy it at Truvalue hardware. Order online and pickup at store.
I did the same thing with Truvalue ordering. Worked great and the price is very good. I did get another version of Floor-dry that was much finer, I think maybe from an autoparts store. The one from Truvalue is good for a general potting amendment, but I need to find that finer one again since it works great in my seed starting mix and I just used that last of it.
Yes I like the finer product for seeds. I could probably screen Optisorb and get some, but that creates dust so I would rather not.
I like Optisorb for rooting cuttings. I’m rooting figs right now under lights. Once I up pot the DE will go in my soil mixes. I always use new stuff to root as it can get algae and such.
Thanks for the clarifying reply.
I always value more scientific/evidence based information. Than feeling or emotional “information”.
I do wonder however. I ofted saw DE advertised for use as dust bath for poulty. It seems very valuable there. But since i don’t have birds as pets, i have no experiance. Whats your view on DE added to poulty dust baths? For external parasites like poultry lice? Are there any studies that tested it? Or is this more in the “wishful thinking realm” to?
Is there a benefit to the coarse vs medium coarse for $2 less? It seems available for pickup near me though otherwise backordered.
Thank you
I am not disagreeing with or trying to say I know more than a trained veterinarian about DE, but I have to speculate there is a good reason that the 55lb bag of powered DE I have on the way from Amazon has every major farm animal pictured on the bad. Additionally no statistics or data was included in the discussion, until @lordkiwi posted the article stating that a statistically significant difference in egg production and reduction of parasites vs control was found for chickens provided DE both in their feed and on them to reduce external parasites, or was my interpretation of that article incorrect? I’m not trying to argue with @Lucky_P for the sake of arguing, I’m just trying to understand the benefits of DE from a scientific perspective. I’m glad Lucky provided input.
Drew, how do you use it as a pesticide? I have food grade DE,but once it is wet , it seems lost effective
Yes it loses effectiveness once wet. A lot like surround clay. I use an air pump pesticide sprayer. I use it for SWD flies. Works pretty good too. Since it is edible I don’t worry about it on fruit. It washes right off too.
Thanks! Diatomaceous earth is so handy.
I only know for indoors, but your sprinkle it where the bugs are, under the fridge, sink, etc. It feels soft and powdery to our giant fingers, but to bugs with hard exoskeletons, like cockroaches and bedbugs, it’s like a bunch of tiny razors that make them dehydrate.
This was very interesting, thanks for sharing. (I know I’m almost a year behind this thread)
I’d never heard of DE working against anything without that hard carapace… but I’m also more than ready to accept that the internet enthusiasts are full of hogwash.
This line made me chuckle “imagine a few razor blades floating slowly by while you are soaking in the pool…” I did imagine that, and now I’m never again going to imagine that! 
I am constantly constrained by having more work than time and need to have some sense of bang for the buck before I add new chores to the maintenance of my veg garden, orchard, small commercial nursery and the many orchards I manage to make a living.
The only ting I use the expensive material perlite for is making potting soils and rarely for improving drainage in extreme clay conditions where raising beds and adding organic matter is not in itself adequate to get the results I want. When I’ve used it as a soil amendment it has been for peaches and nectarines only, because of this species need of very good drainage.
I do not see how perlite breaks down or what would cause it to happen unless it is subjected to mechanical crushing. .Also, I don’t think diatomaceous earth works to improve drainage- quite the opposite I’d imagine- it seems colloidal. Am I missing something- the two materials would seem to not be the least bit interchangeable for what i use them for. I only use DM to suppress certain damaging beetles in my herb garden. It has to be reapplied after rain.
DE is used to stop water pooling in major league ball park base paths. All of the Disney gardens also use DE as to hold water longer. I have posted links to studies showing how well it works at least three times. It is an amazing amendment. But to each there own. I have no skin in the game. It is an excellent solution to certain gardening problems. DE can hold so much liquid it is the best product to absorb oil. I just wanted to pass on the scientifically proven product as I tend to be a scientifically researched based gardener in general. Since so much advice in gardening has proven to be the incorrect. Luckily a lot of university and professional gardeners advance the science. I enjoy my conversations with various horticultural researchers. I learned so much from the professional breeders too. Many are open to helping. Even seeding me seeds to further my breeding efforts in rubus plants. I must say I’m having a blast. I really love working with plants.
The first link was posted in this tread long ago. I lost most of my links,
I always thought this study was a good one.
The issue of DE retaining water is studied.
From the study
Moisture retention characteristics of media’s used in the experiment given in Table 2.
Application of diatomite increased water holding capacity in all of the tensions tested
Also calcinated clay is close to DE, but the pore size is small, so this gives DE the advantage.
From the study
" Pore size of media is a critical physical property which affects water and nutrition
absorption by root system"
In conclusion the study says DE rocks! But we already knew that!
I use it as a substitute for Perlite in my homemade potting soil which is primarily sifted wood chip compost. Seems to work OK, but there’s help from the larger chips and a dry climate.
I guess I should add that the DE was fairly durable which is a significant plus if you use the potting mix over several years.
Drew, the only thing I was questioning was the idea that DM was a substitute for perlite- and the silicon information was interesting to me.
I do think gardeners tend to get a bit over excited about magic or secret ingredients. The fundamentals of soil texture and resulting drainage as well as being sure plants have all the N they need, consistent moisture and adequate sunlight is most of what separates successful from unsuccessful gardeners. But that doesn’t mean something like silicon couldn’t make a lot of difference for any given crop.
The only magic ingredient I’m looking for is an amendment that makes tomatoes resistant to early blight. I also am not very successful at growing eggplant although on some parts of my property it does fine, but I feel I should know why and be able to grow healthy egg plant anywhere on my property. .
I’ve used DE in a few different ways with somewhat mixed results. Like anything, I think the context and what you are trying to accomplish is important. I’ve used a small size DE (one of the oil absorption products) mixed with a seed starting mix at 1 part DE to 4 parts seed starting mix. It seemed to work very well for wicking water up when bottom watering and in the controlled watering environment lead to really nice fine root structures, better than in just the seed starting mix alone which I grew a few cells of as a comparison. It also seemed to keep the plants from going quickly from sturdy to very wilted as they dried out, since I guess the DE had a little more water reserve that was still available when the soil seemed pretty dry.
Where I don’t think it worked as well was in a mix for potted figs I was growing in root pouches. In that application I used 2 parts promix, 2 parts pine fines and 1 part DE (using the largest particle size I could find among the oil-absorbing products). Since these were outside in the elements, they just kept too much water in the pots during a rainy spring and fall when the plants weren’t fully leafed out and using much water. Nothing died, but the root weren’t as dense as the ones I grew in a mix of just 1 part promix and 1 part pine fines. For some reason the DE mix also seemed to get more compacted between repottings, but that is just my perception and I didn’t really test it.
