We don’t use vermiculite in our soil mixes because it is energy-intensive. Turns out there are other problems with it too. The Straight Dope tells all.
The trouble with vermiculite has nothing to do with the substance itself, but rather with a contaminant that’s sometimes found in vermiculite ores: asbestos….
Technically, it’s not just insulation that poses such potential threat, as there are plenty of vermiculite-bearing gardening products around too — it’s added to potting soils to help them hold more water. In 2000 the EPA tested 54 of these: 22 contained asbestos, it turned out, with 8 containing significant amounts and 1 actually releasing asbestos fibers into the air when used. Overall, though, the exposure level for the average gardener was found to be quite low
RSS feed for comments on this post. | TrackBack URI
May 3rd, 2008 at 4:10 am
In the last few months a new vermiculite has shown up on the shelves of bay area garden centers. I believe it claims to be asbestos free (I think it’s packaged by E. B Stone) Do you know anything about this product?
May 3rd, 2008 at 10:31 am
We too have seen the “Asbestos Free” Vermiculite stickers on several brands Vermiculite. I have asked for documentation from our suppliers, but so far no one has followed through with getting it to us and the MSDS sheets that I have been able to download were still showing the old asbestos warnings… I have to say that while I am hopeful they come up with a safer product I think the days of using products made in blast furnaces have to be over, the energy and carbon load on the product is just too high.
We are using rice hulls as a soil additive in place of Vermiculite and it holds moisture as well as adds a nice porous consistency. It also adds silica to the soil just like vermiculite.
Hap
May 4th, 2008 at 1:21 pm
I’ve never used it and now I’m glad. I use pumice a lot as an additive for drainage purposes, and learned that the dust is carcinogenic. Now, I wet it down before using it. It seems that everything is some kind of poison!
Aiyana