Diatomaceous earth after 18 months

Hi folks!

I’m moving a bunch of my nursery stock trees from containers --> grow bags --> raised beds today. Some of them (all bald cypresses) have been in 100% diatomaceous earth for ~18 months.

The DE was thoroughly screened, then thoroughly rinsed, before the trees went in. I live in Louisiana on the edge of zones 9a/9b; this substrate has experienced MAYBE one night below 32F. We get a lot of rain and the humidity is roughly 120% for eight months of the year.

Here’s what the bottoms of those containers and trees looked like today.

Some of that could be dust that I failed to wash out… but I think at least some of it is DE particles that have broken down.

Data for your consideration. :slight_smile:

(I have this suspicion that @BillsBayou might have additional data or insight.)

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What type of DE were you using? I’ve been using it (Oil Dry) for a few years and haven’t experienced that kind of breakdown in any of my trees, including ones wintered outside here in Colorado.

Mine is NAPA Part 8822. I can’t help but wonder if DE is resistant to cold but not to some combination of heat/relentless moisture.

You can get slightly larger particles with the product from Grainger. It’s on my to-do list. I have it, but I ain’t got nuttin in it.

These are going into grow bags? What soil are you using in the grow bags?

A 2-3 year stint in grow bags in raised beds. Grow bags are roughly 50/50 pumice/organic (pine bark mulch and Black Kow).

Question about your prep in washing and sifting. Did you sift > wash > sift > wash over and over and over again? I have found that I need to do that until the water runs clear, otherwise you’ll get tons of dust still there. I got that suggestion from somewhere on da interwebs, but I’m not sure where.

Yes I did. I thought I was being Excessive. :confused:

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I have never worked with DE.
After you wash your DE, do you let it fully dry out before using? Does it become soft?
With Akadama, if it is not fully dry it is very soft and will break down when “chopsticking” during repots.
I have had bags of Akadama with moisture in them and it will be useless if I don’t dry it out.

Possibly, Colorado is relentlessly dry, so it could be the humidity that breaks it down so quickly.

Good thought – I haven’t historically dried the DE out after rinsing it. It could be that. It could also be the relentless humidity of the Gulf states. Or both!

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I just put my trees into DE this year. Yet to see what kind of results I get. Summer did feel a lot easier this year though, but I also got better fertilizer and was more cognizant of my watering. Dunno how much the DE helped in the big picture.

If I remember my research correct, almost all the stuff sold in the US is mined by EP Minerals. The only difference between where you get it is the particle size. The optisorb, the NAPA stuff and a bunch of others are essentially the same.

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I bought some from NAPA as well, but was hesitant to commit because I could crush particles w my fingers. Are there harder grades, or is anyone saying they’ve had success w the same (Oil Dry) product? Particle size seems to be perfect. I am surrounded by some nay-sayers, and I want to experiement with it so I can say, “I told you so.”

The stuff is incredibly cheap! Love that aspect of it.