The benefits of diatomaceous earth

I use diatomaceous earth in my veggie containers instead of perlite for numerous reasons. It holds water whereas perlite does not. It also holds nutrients in the soil longer. It is also a source of silicon which is essential to plant growth. It is a trace element often neglected. Food grade DE also is a pesticide. I was thinking of using it in many ways like to protect berries from the SWD, or to kill numerous insects that emerge from the soil below your trees and other plants.
It also lasts a long time. Perlite will break down in 5 years. I like to add old container soil to my raised beds. Perlite often rises to the top, get’s all over the place. Looks unsightly etc, etc. DE does not, and will last about 50 thousand years.Adding silicon, nutritional retention, increasing drought resistance to your soil in a container or not.
One source of silicon is silicate slags often used in horticulture to add silicon but they often also contain heavy metals. Using DE will give you all the benefits
of silicon without adding any heavy metals to your soil.

Food grade DE is available all over. If you wish to use the larger granular size as a soil amendment to replace perlite you can obtain it in various oil absorbent products like Optisorb and Napa floor dry. Always check ingredients to make sure it is 100% DE.

Here are some interesting studies and write ups about DE or silicon. The first study is really worth looking at, It is highlighting a product that has large amounts of DE. It goes into all the benefits of using DE.


Great info! I have seen the use oil absorbants mentioned in potting mixes but never knew that it was DE. Thanks for sharing!

Again make sure it is, clay is used too. Which also is a decent soil additive, turface is often used. A heat fired clay. Although IMHO DE is much better.

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Doing the math, about 170#/acre. Would be pricey for row crops but doable for horticultural crops. I’ll try it on raised beds this next year. Science makes sense, if a plant grows in a soil with any sand in it, makes sense it will require silicone. Is this DE the DE used for an insecticide?

In the study it is similar. The first study listed uses a product that is freshwater DE, If you looking for the silicon content, food grade will work, so yes same as used for an insecticide. The calcined DE I use in place of perlite may not give off silicon readily. I add the food grade as an additive also, like one would add green sand, or azomite or other soil additives.
I think the calcined larger form I use in place of perlite has all the benefits of the kind in the study except maybe the availability of silicon. Although it may?? Using the food grade as a pesticide or an additive can supply the silicon. I use both, as the larger granules work well for potting soil. Then after a few years it all ends up in my raised beds.
One warning though is be careful not to breath this stuff at all. Or the dust with perlite or vermiculite too. It is dusty so be careful.
How much available silicon in the food grade or on the granular is unknown. Using Argipower products would be best but it is an Australian product.
You can add silicon in other ways such as this product
The other beneficial properties of DE like water and nutrient retention is true of all forms of DE.

I used some yesterday to pot up an amaryllis. I used the O’Reilly auto parts product, Optisorb instead of the Napa product. Based on a recommendation here. I did the ‘gritty mix’ thing, not that it makes much difference with an amaryllis.

You’re right. Its a nice product, quite obviously a good substitute for perlite.

I also like to use it mixed with seed starter mix to start seeds. It helps defeat the hydrophobic properties of the peat moss in the mix. And stretches the mix too!
I also make a gritty type mix for my cacti. I like to use this rather expensive river rock mix with added pine and some peat too.

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Rather then start a new thread I dug up this old one.
I wanted to mention that not all clay sources are made equal. If your looking to source Daotomaceious earth cheapy as Automotive Oil dry. Be sure to check the spec sheet for the (Chemical Abstracts Service) number

Diatomaceous earth: CAS# 61790-53-2

Fullers Earth AKA Attapulgite CAS# 8031-18-3


I recently used some other brands and the particles were smaller. i recently found a source for the best price for Optisorb which has the largest particle size. I was using it yesterday and was very happy to see the larger size. So I found out Grainger sells it online for pick up at the closet store. In the days of Covid they bring it out and load it for you into your vehicle.

What is the ratio of DE you use? Say per gallon pot of soil.

I don’t use as much as the studies suggest. I make my own soil and my ratios are 3-1-1-1/2(DE). In the studies the most effective was 1/3 of mix. I can’t afford that, I have over 100 containers with plants.

This study said 30% was the best results but improvements with less too. this is a cool study on strawberries

Here is another study
From the study
In fact, diatomite treatment raised all growth
criteria , chlorophyll a and b, total pigment, total
soluble sugars, total sugars, total soluble nitrogen
and total nitrogen concentrations. It also increased
the values of phosphorus, potassium, calcium and
magnesium and induced new electrophoretic protein
bands and new polymorphic isozyme (EST,POD,CAT
and ACP) electrophoretic bands while caused the
disappearance of another bands. Moreover,
diatomites increased the photosynthetic rates , the
leaf stomatal conductance , the net intercellular CO2
and the %of leaf relative humidity (LRH). Reversibly,
diatomites caused the decrease in each of transpiration rate and the concentrations of each of
carotenoids, sodium and iron.
Collectively, Si fertilization has a multiple effect on
the soil-plant system. Firstly, improved plant Si
nutrition reinforces plant protective properties against
diseases , insect attack and unfavourable climatic
conditions by enhancing the morphological features
concomitant with the physiological and metabolic
activities of plants. Secondly, Si optimizes soil fertility
through improving soil water, physical and chemical
properties and maintaining nutrients in plant available
forms (Matichenkov and Kosobrukhov, 2004).

It is thus evident from this work and from the
literature that, Si in the from of diatomites or other
similar natural products should be used more
extensively than they are presently. Frankly, silicon
fertilizers are not used more extensively world- wide
because there is a critical lack of specialists working
to show the importance of Si as a fertilizer material .
Moreover, knowledge of benefits of Si fertilization
must be translated into practical and economic
strategies based on suitable safe products to
underpin impotents in crop yield and quality while
arresting degradation of the soil environment. Further
studies should be also focused on Si uptake and
translocation in various plant species. This process
varies greatly among plants depending on whether
they are accumulating or non- accumulating and on
the controlling genes. Such uptake genes needs to
be cloned, isolated and characterized in different
plants in the near future like those of rice plants
.Furthermore, given that most plants, particularly
dicots, cannot accumulate Si in large enough
amounts to be beneficial, genetically manipulating the
Si uptake capacity of the roots might help plants to
accumulate more Si and, hence, more able to
overcome both biotic and abiotic stresses.

The author has a point! The essential elements chart completely ignored silicon. I know not considered essential. Which is obviously incorrect. Leaving off Si is as bad as leaving off N or P or K. .

I can’t think of any one amendment that does more for you other than DE except maybe fertilizer. Notice the author considers it fertilizer.
Ever wonder why Disney Gardens look so nice? They use DE in all of them.


Interesting, thank you for sharing! After I up-pot cuttings rooted in DE, I toss any remaining DE into my raised beds. They eventually get worked into the soil. Glad to hear that it’s beneficial!


Yes I do the same thing. Well I use in containers, and when I up pot, the old mix goes into raised beds. This thread is five years old, all my beds now have some DE in them. .Not easy at times but managed to put a lot of old potting soil in them.

Thank you, Drew. I used it in 2018 and probably mix 1/3 ratio. It’s hold too much moisture in the pots. I think I’ll do less this year.

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Learn something everyday. Have several bags of it but never used it, probably not knowing enough how to use it . Now I do, thanks Drew.


Turface is another great additive with similar properties. I don’t know about the availability of Si in it, but it behaves much the same as DE otherwise. It’s calcined clay, basically kitty litter that’s been kilned at high temperatures so that it’s stable and won’t clump or turn to mush. It acts like gravel that absorbs water, so all the excess moisture drains away and there is moisture in reserve. Almost impossible to overwater. I’ve grown plants in straight Turface with good results, but you do have to water more frequently than if it’s blended with something else. It produces amazing root systems.

You can either buy pre-sifted stuff from bonsai suppliers or on eBay, or you can find a landscape supplier or university athletic dept (they use it for the baseball infield) to source larger quantities.


I have been using one of the calcined clay oil absorbent products to plant the waterlilies and other plants in my water garden. Do you think the Optisorb large particle DE would be suitable for that use as well? Completely submerged, that is?

If the clay is working DE should work too. Worth trying to see at least. Although may attract algae. I would try a small area to test.

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I wanted to bump this thread and say thank you to Drew for pushing his “DE agenda” on a couple different general threads I’ve read, or else I might have missed this one. And thanks to @mamuang for the suggestion on NAPA brand DE.

I was searching the collective knowledge of the internet for information on cat litter /NAPA DE and other types of DE and came across this bonsai forum thread The Great D.E. Thread - #17 by el_cheezer - Horticulture - Mirai Forum

Towards the bottom there is a video posted comparing various DE. I haven’t watched yet but plan to before purchasing anything.

There are a few things to consider that I hadn’t seen specifically mentioned.

There is the food grade pulverized powder form used for livestock vs the larger sized oil absorbent size
Has anyone found inexpensive cat litter made of DE that is less expensive than the oil sorb products mentioned? I know some cat litters use clay (Bentonite based?) products. We use Bentonite medium chips at work to seal pipes through embankments etc for the expansion properties, but I’m wondering if the heat treated versions are also effective for horticulture purposes, and if there is a significant cost difference vs DE making it worth a shot? It seems to me that there is a clear advantage to DE but I wanted to ask the simple questions, because sometimes it’s good to know the “why”, not just the proper answer.

Additionally on this thread Napa Oil Dry part no. 8822 | Page 9 | Bonsai Nut
Effects of kiln heating are discussed. Apparently the napa product is not heated vs optisorb being a calcinated fired product, which brings me to my next point of contention - may be why @sorce had a worm kicking in a tree with, if I remember right, was in 100% napa DE

I don’t want to murder all of the earth worms living in my raised garden beds. I know powdered DE is great for keeping unwanted insect critters at bay, but I like the free earthworm castings in my beds too. Is it possible to have your cake and eat it too with the napa product?

My final thought for now, is the discrepancy in volume /weight on napa vc optisorb. Napa comes as a 24 quart bag vs optisorb 25 lb for about the same price. Which is the better deal per lb? I can’t compare weight vs volume for costs, although I could probably estimate the dry weight on napa based on avg particle size. Any thoughts there?

Still trying to learn over here.


Opitisorb is the best just because of it’s large particle size. Turface is used for the same purpose as I use DE, but Turface is a horticultural product. It is a heat treated clay. It is not as good as DE but it is darn close.
The way to test a product is to soak it, drain the water, then freeze it for 24 hours. If it doesn’t change to goo after thawing the product should work.
Powdered DE used to kill insects works by impaling the insects so they bleed to death, can take hours.
Particulate DE does not have this sharp glass property. Insecticidal DE only works on bugs with an exoskeleton. It does not harm worms.
What is Diatomaceous Earth? How to Use DE for Garden Pest Control ~ Homestead and Chill.

This article states something important. that powdered DE works by mechanical action not chemical, It also states it’s a great way to get unwanted pests out of your worm bin. If DE is hurting worms, something is extremely wrong with the DE. This worm farming site endorses the use of DE to rid worm bins of pests.

Optisorb is expensive, the cheapest place I found it was Grainger’s. If you have one near you you order online and it is shipped free to the store of your choice. $10.40 for 25 pounds. Grainger sells other DE products, but Optisorb is the best one.