I just came across this topic & want to jump in.
Pssst... Jiffy I think you got "vermiculite" confused with "vermiculture".
Originally posted by Jiffymouse:
vermiculite is also called worm dirt, worm castings, or worm manure.
It's easy to get the 2 names confused, cuz the word "vermiculite" is derived from the Latin 'vermiculare' (*to breed worms).
"Vermiculture" is just a fancy name for worm dirt, worm castings or worm manure.
Vermiculite is a mineral which is mined in only a few places on the planet. (Kenny was close... it's actually hydrated laminar magnesium-aluminum-ironsilicate!) It resembles mica when it comes out of the ground, but when it's heated it expands into pieces that look like small worms. The extreme heat from the "exfoliation" process causes it to be sterile, which makes it perfect for use in soil amendment mixtures. Used in gardening in its expanded form, vermiculite aids aeration, improves moisture retention & helps the steady release of added fertilizers while providing potassium & magnesium of its own.
Perlite isn't a trade name but a generic term for a natural siliceous rock. The characteristic that sets perlite apart from other volcanic glasses is that when heated to a certain point, it expands from 4 to 20 times its original volume. The expansion process is what gives Perlite its white color. (As Jiffy mentioned, vermiculite is usually brown or black.)
Originally posted by patches1414:
Perlite also has a more neutral pH than vermiculite.
It's my understanding that perlite is classified as chemically inert (since it is a form of a natural glass), & its pH is 7 (neutral). According to The Schundler Company (one of the largest U.S. distributors of perlite & vermiculite), the pH of vermiculite ranges from 6 to above 9.5, depending on the mine it originated from.
Vermiculite has been a point of research & a topic for discussion at our house for many years, & this is why I know some things about it...
My husband was born & raised in Libby, Montana, & I lived there for many years after we were married. Vermiculite mining began in Libby in 1924, & the community health hazard from the dust of vermiculite became too apparent for the W.R. Grace company to continue their operation after 1990. (Lawsuits are numerous & ongoing, as the company allegedly knew the danger but kept it to themselves.)
- Before we knew there was a health risk, we would drive over to the vermiculite transfer site & they'd dump a load into the back of our pickup, so we could take it home & till it into our gardens. Since it was "raw" & hadn't gone through the exfoliation process, it took a lot more of it to aerate our heavy clay soil than it would have if we'd have purchased the processed product... but it was limitless & "FREE"!
- Ignorant of the asbestos danger in vermiculite dust, we allowed our kids to enjoy the piles of vermiculite as they would sandboxes, until we got around to working it into the gardens!
- The house my husband grew up in had been insulated with raw vermiculite (as were many of the homes built in the 40's - 60's), which was handed out to the locals at the transfer site!
- Before my mother-in-law died of complications from Asbestosis (a respiratory disease caused by inhaling asbestos fibers), she sold the house... but she had to have the vermiculite "insulation" evacuated from the attic & walls by a Hazmat team, before her buyer could secure a lender.
It's my understanding that the manufacture of vermiculite products which have the ability to create a dust have been discontinued. (In the gardening world, vermiculite is being replaced with perlite, which many of us don't care a lot for, cuz it floats to the top of potting soil!)
But... getting lose, processed vermiculite away from the public isn't happening fast enough for my liking (as well as the other people who have suffered losses from the mining operation). I still see vacuum bag "air freshener" (which is made up of 100% expanded vermiculite with perfume added) on store shelves... which is one of the worst ways to use such a product, as the airborne dust is where the danger is!
BTW Webwise, I like your Eeyore signature button!
Good luck with your gardening... it's the best stay-at-home adventure you'll ever find & I'm glad you joined us!