HELP! Food Grade Diatomaceous Earth

[Mollisol]

Questions on Food Grade Diatomaceous Earth. I understand FGDE Is sprinkled on the top of dry soil to help with bugs. I have read some people lightly dust the plant itself also. Anyone have experience with this?

[homegrown]

Yes to both...sprinkle over top of dry soil. I have also dusted main stem and stalks while battling thrips in past grows.

[Mollisol]

Ok to dust the leaves and preflowes as well? My plants are all in veg.

[homegrown]

Leaves yes, i would avoid pre flower and flowers. What kinda bugs are you dealing with?

[AGH]

Remember, Diatomaceous Earth works by essentially cutting the exoskeleton of the pest which dehydrates their bodies and they die. This means that they have to crawl over/through it for it to be effective which is why it's often dusted on top of soil. Pests lay eggs, hatch, crawl around, and mate in/on the soil making DE very effective. It's also great as a preventative measure to keep any pests that hatch from eggs that are in your soil from gaining a foothold.

While DE won't hurt your plants by dusting them, there are more effective ways to kill pests that are on the actual leaves. I have successfully used Neem Oil and Insecticidal Soap. I copied the below from a post I made on another thread which may help you see how I incorporated DE when encountering pests in a previous grow:

I grow organic so when I had pests in a previous grow, I used a triple-pronged approach. If you're growing synthetic, you have a few more options but below is what I did. This is for veg...in flower, make sure to not get anything on the buds, don't spray anything on them within 2 weeks of harvest, and I recommend NOT using Neem Oil in the flowering stage at all.

- Day 1: After watering, I sprayed the plant with Insecticidal Soap. I would also spray the top of the soil with it. Insecticidal Soap is a contact killer and works by destroying the waxy coating on pests and drying them out.
- Day 2: Once the top of the soil was a little dry, I'd sprinkle Diatomaceous Earth all over it. This kills the pests by cutting through their exoskeletons and drying them out.
- Day 3: Take a deep breath and know that this isn't the end of the world, just some pests.
- Day 4: After watering, spray the plant and top of soil with Neem Oil. This works as a systemic killer as it enters the pest's body and disrupts their reproductive system.
- Day 5: Once the top of the soil is a little dry, another round of Diatomaceous Earth.
- Day 6: Another deep breath and reminding myself that this is going to take 3-4 weeks before it's completely effective.

That last part is important. You need to continue treating even after you stop seeing the pests. The lifecycle is such that about the time you finally eliminate all of the adults and you take a victory lap, the eggs that are in the soil hatch and the problem starts again. To eliminate the pests, you essentially have to create a population collapse and doing that takes several generations (for the pests, not you) to accomplish.

[Rwise]

A note on DE, when it is burned/heated it forms crystals, these crystals are deadly to everything, so no to using it on buds

[Ckbrew]

Good to know.

[Mollisol]

I dusted the soil with DE. I used a salt shaker which someone had suggested and it worked very well. I also tossed about a tsp of rice into the salt shaker. The rice in the shaker helped the DE dispense better. And I hope will help keep it dry and from clumping up.

[AGH]

Nice! I use a sieve to dust it on. You can even go heavier in the application if you want.

A little note, before you water, work the DE into the top inch or so of the soil. Sometimes if you just water right on top of it, it makes a sort of a crust and the water has trouble soaking in. Not a big deal, just something to make your life a little easier :-)

[Sixwinds]

I like the salt shaker idea - I use an accordion blower? that came with my DE bag, but it kind of sucks.

It may just be the pictures but to me the plant on the right looks like it has the worst of the infestation. If you can move or isolate or even cull that plant it might help save the other two. I'm no expert and as such take no responsibility for my advice being good or bad :P

Good luck!

[Mollisol]

Would you all agree adding a thicker layer on the soil would be beneficial? I can't imagine it would harm anything. That being said its not exactly cheap either. I don't want waste it.

[Gingerbeard]

My experience is dusting the top of the soil with DE does little to no good. There are too many surfaces under and around soil bits that DE does not get around as much as it should. It will also wash into the soil the first time you water.
A thick enough layer would need to be thick enough to cover the soil half an inch, tamped a bit. Removing what you can of the soil without hurting roots will give you the best treatment for soil nasties. Mix the soil with DE and replace. I put enough in to make my soil turn dry and gray.
Also keep fans going across your soil. Bugs can't land so well in the wind.
There are very few things you can do to budding plants when they get infected. Many of those things will not be affected by DE. Unless you get into bud washing, you are guaranteed to have DE in your buds if you go that route.

[Gingerbeard]

And I question the need for FGDE. It is not being ingested in any use of the plant. I'm not saying to get the stuff from Chernobyl. But why, exactly, FGDE?

[AGH]

(Gingerbread, none of the below is intended to minimize your advice or experience :-) and thanks for adding the fan blowing across the top of the soil as that is important and extremely effective as well when used in a multi-pronged pest management program!)

The reason Diatomaceous Earth works is that it cuts the exoskeleton of the pest and dehydrates them which causes them to die. It's non-synthetic, it's not a chemical, and it's certified organic. Instead of a chemical (ie. pesticide) method of eradication or prevention, it is essentially a physical barrier. It prevents pests that are in the soil from getting out when they hatch because it kills them and it prevents adults from getting into the soil to lay their eggs. Imagine it being something like razor wire surrounding a fort instead of a nuclear bomb or mustard gas.

The best way to use it is in conjunction with other methods so that you have a robust integrated pest management sort of a way of doing things.

I've had very good success using it. Yes, you have to reapply after watering and yes, if you put it on when your circulation fans are running, it can blow around. I've never used half an inch of it, just a good solid dusting does the trick. And it's okay if you don't get EVERY nook and cranny on the soil. Pests walk/crawl all over the place on top of the soil so as long as you get an amount that looks like the picture you'll be good.

Is it perfect? No. Is any single pest management strategy perfect? No, that's why you use the multi-pronged approach that I mentioned in my post above on 10 March.

Another benefit is that if you're growing organically, it adds micronutrients into the soil as well as keeping it aerated when you mix it in before watering.

Your mileage may vary, everyone's situation is different based on their needs, growing conditions, etc!

P.S. What a great place to get so many different opinions and experiences! GWE Forums really are a model for society :-)

[90Gizmo]

That may be a billion times more than you need. Stir up a tablespoon in your spray bottle and spray it where you want it. It'll dry and then it will still be 100% effective. I learned this as part of a termite control spray. (I've never tried this on plants.)

[Gingerbeard]

I can say I have had fungus gnats crawl all over that amount of DE.

[Gingerbeard]

's all good, AGH. We all have our own.
Funny this came up, though. I had been thinking about making a slutty out of DE and water. That would allow more penetration. Nothing for me to try as I have advanced to coco/perlite and have had no medium baddies, since.

[Blowdout2269]

A slutty? Penetration?
And my minds in the gutter...
Lmao!

[Gingerbeard]

...or slurry.

[homegrown]

What kinda bugs are we trying to eradicate? If its fungus gnats DE isn't very effective i have found. I've seen them coming out of holes in the side of hard plastic pots when i grew in soil. Lotsa wind an a shit ton of sticky traps works wonders on them. When i had to deal with thrips i used a small soft bristle paint/craft brush and dusted the stalk starting at the soil and brushed it up all the way into the plant. They wont cross the stuff. Also remove any leaves that are touching the soil and dust DE on anything that is connected to the plant(plant ties and wires for LST and poles etc).

[Rwise]

Diatomaceous Earth, known as “DE” for short, is a very fine, chalk-like white powder. It is made up of the fossilized remains of single-celled aquatic microorganisms called diatoms. In a nutshell, it is ancient phytoplankton. Diatomaceous earth is found naturally in sedimentary rock and mined to use in industrial products, swimming pool filters, as an organic insecticide, in pharmaceuticals, cosmetics, and even in food.
The diatoms that make up DE have tiny rock-hard shells. Those shells are made of silica, which happens to be one of the hardest substances on earth. Fun fact: the Earth’s crust is 59 percent silica, and the main constituent of more than 95 percent of all known rocks.

DE will harm any target insect that comes in contact with it, whether they’re directly dusted with it, or they walk over it later. That is…. as long as the DE is dry.

The main drawback with using diatomaceous earth is that when it gets wet, it’s rendered far less effective.

inhalation exposure. It is not healthy for humans or animals to inhale fine diatomaceous earth dust.

Safe enuf if used properly, however IMHO it does not work well, lots of enfo out there!
Gingerbeard with it being basically silica it can be used by the plant. However IDK if its effectively absorbed, and cheaper ways to get silica.