(1) Perlite is strictly for drainage.. it will not retain ANY water (2) Vermiculite also promotes drainage BUT will retain some water. (3) I use water to mist all plants VINEGAR is a post emergent herbicide (IT KILLS PLANTS) even though it is also a fungicide (Kills fungus)

I think it is a little hard to find vermiculite. PBS had a program on Libby, Montana, that used to be the mine for vermiculite. A good portion of the town people got cancers. Put that in your search window, and read about vermiculite. After watching the program, I don't want to use the product anymore, even if it is hard to find.
Darlene

There were some mines such as you mention where the vermiculite also contained asbestos. Vermiculite is no longer available from those sources so you should have no fear of using it. It is my practice to keep my vermiculite stored in a moist condition to prevent breathing the dust when I do use it. Al

Hi, Proudgm.

Perlite is actually a form of porous glass that is made from a mineral called obsidian (or an aluminum silicate rock). It's heated and kind of popped like popcorn. Vermiculite is mica that is treated in much the same way. Trapped moisture expands and creates lots of air pores in both products.

In soils, perlite promotes drainage and improves porosity. It's also effective for starting seeds & cuttings. Actually, perlite holds quite a bit of water @ about 3/4 quart per gallon of perlite. The dry weight of perlite is about 7 lbs/cu ft. Wet, it weighs about 18 lbs for the same volume, so it holds more than 2-1/2 times it's weight in water. Vermiculite is about the same density, and has a even higher capacity for holding water and a very high cation exchange capacity. It also contains magnesium and potassium that are available for plant uptake, but it is not very durable and will compress if handled when wet. It also has a slightly higher pH than perlite.

Misting isn't necessarily a good thing for plants - and while vinegar with it's acid component, at toxic levels is a herbicide, it is also often used as a container soil acidifier in solutions up to 1/4 cup per gallon. It is also an effective fungicide at 3 Tbsp. per gallon of water - especially if you add a Tbsp. of sulfured molasses to the mix.

Al