Tomatoville® Gardening Forums - View Single Post - Diatomaceous Earth as a seed starting medium

paradajky · December 8, 2021

Three questions for laughs:
1. Does calcined DE exist any more for the retail customer
2. Is it important to use calcined in this application given the short time seedlings are kept in it before up-potting
3. Why does it seem that seedlings have better performance in DE vs. something like Turface (or other calcined clays)

I went down the rabbit hole a couple years ago into the 1-1-1 gritty mix, and one option included subbing DE in the mix for turface and/or perlite. What I learned was the products listed 5-10 years ago have all changed, and it doesn't seem like we necessarily get the same things you all used to get then vs. now.

Here's some of what I learned. "100% natural" DE found in the automotive absorbent products was not calcined, and therefore, would breakdown into mush sooner. Calcined means baked at high temps (i.e. a kiln), which improves the longevity and absorption of the product.

Before EP minerals acquired Moltan, products such as Napa #8822, Floor-Dry, and ultrasorb were calcined. Unfortunately, it seems like all of them now are no longer as such. You can confirm this by looking at the packaging and SDS sheets for the various products - if it says "100% natural", or ingredients/SDS exclude "calcined" or use the word "natural", then this is the regular DE. Napa actually includes two SDS sheets, one is calcined, other is natural. I think that's to make up for any old stock left out there. Autozone uses the the old Moltan sds from 2007, which simply lists it as diatomaceous earth.

EP Minerals' description on their website lists Floor-Dry as being baked in a kiln, which complicates things but their other *sorb products are natural.

Somehow I suspect this isn't a problem for seedlings from a longevity standpoint, however, this may be why there are differences in pH and different levels of success people here have with the method.

I have a bunch of screened turface in my garage that I'd like to find a use for, and was considering using it to start next season's seedlings vs. purchasing yet another product to take up space in my garage like DE :p

Thanks for your time!

December 8, 2021	#830
paradajky Tomatovillian™ Join Date: May 2021 Location: Coastal Southern CA Posts: 164	Three questions for laughs: 1. Does calcined DE exist any more for the retail customer 2. Is it important to use calcined in this application given the short time seedlings are kept in it before up-potting 3. Why does it seem that seedlings have better performance in DE vs. something like Turface (or other calcined clays) I went down the rabbit hole a couple years ago into the 1-1-1 gritty mix, and one option included subbing DE in the mix for turface and/or perlite. What I learned was the products listed 5-10 years ago have all changed, and it doesn't seem like we necessarily get the same things you all used to get then vs. now. Here's some of what I learned. "100% natural" DE found in the automotive absorbent products was not calcined, and therefore, would breakdown into mush sooner. Calcined means baked at high temps (i.e. a kiln), which improves the longevity and absorption of the product. Before EP minerals acquired Moltan, products such as Napa #8822, Floor-Dry, and ultrasorb were calcined. Unfortunately, it seems like all of them now are no longer as such. You can confirm this by looking at the packaging and SDS sheets for the various products - if it says "100% natural", or ingredients/SDS exclude "calcined" or use the word "natural", then this is the regular DE. Napa actually includes two SDS sheets, one is calcined, other is natural. I think that's to make up for any old stock left out there. Autozone uses the the old Moltan sds from 2007, which simply lists it as diatomaceous earth. EP Minerals' description on their website lists Floor-Dry as being baked in a kiln, which complicates things but their other *sorb products are natural. Somehow I suspect this isn't a problem for seedlings from a longevity standpoint, however, this may be why there are differences in pH and different levels of success people here have with the method. I have a bunch of screened turface in my garage that I'd like to find a use for, and was considering using it to start next season's seedlings vs. purchasing yet another product to take up space in my garage like DE :p Thanks for your time!