[Plant-education] Re: vermiculite and other dusty materials

David R. Hershey via plant-ed%40net.bio.net (by dh321 from excite.com)
Tue Oct 17 19:28:51 EST 2006

I wouldn't think a special dust control system would be needed for a
college greenhouse potting bench. Do you mix your own potting soil or
buy it premixed? How often would the potting bench be used?

High levels of asbestos in vermiculite is mainly a concern in
vermiculite used in building insulation. Vermiculite from the Libby,
Montana mine was high in asbestos but that mine closed in 1990. The
websites below mention that horticultural vermiculite is usually low or
lacking in asbestos. If you moisten your potting soil prior to use,
there should be no problem of vermiculite dust. Many commercial potting
soils contain little vermiculite anyway. It should be standard practice
to moisten potting soils prior to planting because they are often
difficult to wet after planting.

In my experience, horticultural perlite is much more of a dust problem
than vermiculite. Perlite dust is a nuisance and can cause temporary
discomfort but is not considered a long term health hazard like
asbestos. When I used perlite to root cuttings, I would cut open a
corner of the bag and spray water inside with a spray bottle to
eliminate the dust. That technique would work when pure vermiculite is
used to germinate seeds.

David R. Hershey


Vermiculite Consumer Products

Vermiculite - Health, Safety and Environmental Aspects

Health Effects of Perlite

Carl Pike wrote:
> In designing a new greenhouse, we are concerned about dust during
> mixing and potting operations.  This leads to 2 questions -
> 1. Can anyone recommend a system for dust removal that could be
> installed over the potting bench?  Someone suggested the devices used
> around woodworking machinery.  We've heard about "snorkels" that are
> used in medical settings.
> 2. I have heard particular concerns about the safety of vermiculite.
> I was "brought up" using vermiculite for seedlings (peas, oats, etc.)
> either in the light or dark when the growth period was just a week or
> two.  Are there some types of vermiculite that are of less concern?
> What are people using instead?
> Many thanks.   Carl
> --
> Carl S. Pike
> Harry W. and Mary B. Huffnagle Professor of Botany
> Department Chairperson
> Department of Biology                Phone (717) 291-3958
> Franklin and Marshall College       email CARL.PIKE from FANDM.EDU
> P.O. Box 3003                            fax (717) 358-4548
> Lancaster, PA  17604-3003  USA
> Physical address (for UPS, etc.)
> 415 Harrisburg Ave.
> Lancaster, PA  17603

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