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Diatomaceous Earth

Has anyone used diatomaceous earth with their carnivorous plants?

For anyone unfamiliar, diatomaceous earth is a dust that's not harmful to humans but easily destroys insects' exoskeletons and respiratory systems. I have an issue with gnats and happen to already have some diatomaceous earth for an unrelated purpose (well, still for killing bugs). The idea is that a layer of diatomaceous earth atop the soil prevents the adults from landing on the media to breed there without dying. Would this be harmful to my plants in any way? Would I need to wash the diatomaceous earth before use? If you've tried this what were your results?

The plant that appears to be harboring the gnats is a VFT that came from a hardware store death cube (although they might be in the other plants too). It's done fine over the last few months and although its growth has slowed, it hasn't gone fully dormant and likely won't this year. To my surprise, when I was inspecting the plant I also found a number of small sundew seedlings. Apparently some capensis seeds made their way into the VFT's pot. The sundew has done a good job of catching the adult gnats and is doing great, but I'm concerned about what the larvae must be doing to the plants' roots.

So, the question is how to vanquish the gnats without damaging the VFT or the seedlings. I don't want to transplant the seedlings at their current size, and I'm concerned about infesting a new pot with the present larvae anyway. Of course, I'll eventually be repotting with carefully rinsed fresh media. In the mean time, I want these things gone!
 
I wouldnt..
diatomaceous earth isnt really a "dust"..its actually fossil diatoms..its VERY sharp yet very small..imagine a ball of microscopic razor blades..yes it kills bugs because it cuts them up..but wouldnt it also cut plant stems and roots then too?

bugs in and on the soil is virtually a non-issue for CP's..
using diatomaceous earth for CP's would be, IMO, a solution withough a problem..

Scot
 
It's used as a growing medium in hydroponics so I don't think that it's a problem for plants.
 
when using D.E. You have no worries about the plant or rootsystem being compromised. You use D.E on the first inch or so of the substrate. As a barrier treatment. What you do have to worry about is using this stuff inside.

Growing Inside With good ventilation, you may be breathing in a lot of airborne "dust"that makes perlite dust look like talcum powder in comparison! Think of it as asbestos on steroids. :)

I wouldn't recommend it either since there are many other options to explore first that have been proven over again.

Happy growing!
 
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Growing Inside With good ventilation, you may be breathing in a lot of airborne "dust"that makes perlite dust look like talcum powder in comparison! Think of it as asbestos on steroids. :)

Exactly what I was thinking. It would shred your lungs at a small scale, having big effects. Basically, sneezing anywhere close to it would kick a lot of it up, turning it into tiny precision razor balls of respiratory death, like little ninjas assassinating your lungs. Ceramic powder is bad enough, this stuff sounds worse.
 
I could add my bit of experience here...

When I used to grow succulents I would pot them in almost exclusively Aquatic Plant Soil until I ran out and nobody around here sells it. So I inquired on the cactiguide forum what else would be similar and read about some folks using NAPA Floor Dry product #8822 which is an expanded diatomaceous earth clay like substance that absorbs water and dries out in a few days like APS does. It was perfect for my succulents.

So having a 25# sack of it I decided I would try the same stuff in a peat based mix for a ping and a couple dews. This didn't go over well at all. Within 3 days all 3 of the CPs had turned black and shriveled in on themselves. I've repotted these types before and never lost them in such a fast amount of time.

I've had sinus infection ever since using it 2008/2009 so I'd really stay away from diatomaecous earth unless you're gonna use it for succulents AND grow them outside to avoid the dust swirling around indoors if you're using fans (which I did).
 
since you have this problem in vft and they need to be in cold conditions to go dormant . the cold should kill most if not all the gnats
I don't know where you live its not in your profile, but if it gets cold outside put your vft outside
 
Thank you for all your help!

Is there a more proven method to get rid of gnats that you would generally recommend? I just don't want them destroying the dionaea's root system. If it's at all possible, I'd like for those surprise capensis seedlings live through it.

In regards to using diatomaceous earth inside— I have been using it as a preventative measure ever since I moved out (fled?) an apartment building that came with a bedbug infestation. The most important things are to avoid inhaling it is during application and to apply it carefully and sparingly. It doesn't really get into the air as long as fans aren't set on or aimed towards the ground. So far (over 6 months with minimal application and nearly no bugs of any kind in the treated area) it's been noticeably easier to breathe here than in the old place where the pest company was liberally spraying some nasty-smelling chemicals. However, I admit that's not a great basis of comparison for lung health!

It seems that to coat the top of a plant's soil, there could be enough in an exposed place to create an air quality problem. Maybe this could be ameliorated by adding gravel on top? Would a non-lethal barrier be enough on its own to stop the gnats from breeding in the soil? One additional concern is whether any possible impurities could leech out of the top layer of DE into the water.
 
Are you talking about fungus gnats? If so then mosquito dunks (BTi (Bacillus thuringiensis subspecies israelensis)) or Steinernema feltiae are a common treatment.
 
  • #10
It seems that to coat the top of a plant's soil, there could be enough in an exposed place to create an air quality problem
You can water the DE into the soil after spreading it on the top. Once its wet theres no dust. I've used it for years on my houseplants.
 
  • #11
I wouldnt..
diatomaceous earth isnt really a "dust"..its actually fossil diatoms..its VERY sharp yet very small..imagine a ball of microscopic razor blades..yes it kills bugs because it cuts them up..but wouldnt it also cut plant stems and roots then too?



I believe the point is that it gets into the softer membranes that are present at the joints of insects, and when the critter tries to move, these membranes get torn up. Because the plants are moving around, it wont harm them. Also, they have the epicuticular wax which would protect them from any "scratches."
 
  • #12
I am in Cincinnati, OH.

They appear to be fungus gnats. If I can get rid of them, I'll remove the capensis seedlings and try moving the vft to a colder location.
 
  • #13
I feel you on the bedbug issue. Had them in October, it was awful! I could have played connect-the-dots on my body.

I usually take care of fungus gnats by terrestrial bladderworts and sundews. I've had a drastic reduction in their numbers since I started growing the two side-by-side.
 
  • #14
I currently have a fungus gnat infestation. I've never used mosquito dunks, but read about them elsewhere on this forum - http://www.terraforums.com/forums/showthread.php?t=128712. I am currently using a combination of fly papers and Steinernema feltiae, and there are noticeably fewer adult flying around.
 
  • #15
I'm with mobile on this. I've been using mosquito dunks since a particularly terrible fungus gnat infection this last spring. It works like a charm. I use dunks where I have tray watering and with the other plants I simply use a 1" mulch (rinsed pea gravel, silica sand, and turface all work fine). If you can't find it locally in hardware store or nursery, you can find them online quite easily. No need for potentially dangerous DE (Bti, the bacteria in mosquito dunks, is harmless to pets and humans). Good luck!
 
  • #16
Well, it's supposed to be harmless since it is thought that the toxins are metabolized in mammals but this study found Bt toxins in the blood of pregnant women from eating GMO corn that produces the Bt toxins:

http://www.ncbi.nlm.nih.gov/pubmed/21338670
 
  • #17
I'll have to look into the mosquito dunks. They look like an effective, non-invasive option. It looks like a hardware store will likely have them even if the local nursery does not. Ultimately, I think I'll also add a layer of mulch, gravel, or sand.

I am growing a (currently solitary) sundew nearby that has been benefiting from the gnats and keeping the adult population very small, it's just that the larvae can't be good for the VFT.

Wire Man— so sorry to hear that! It's such a difficult problem to have. The worst part is the ongoing paranoia about infestations. I've been cautious to excess ever since (thus the preventative DE treatments), especially as the bugs are particularly prevalent in Cincinnati.
 
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