Date: Tue, 10 Feb 1998 07:36:28 -0500 From: Rand Nicholson <writserv@nbnet.nb.ca> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg536$foo@default> Subject: Re: Perlite v Polystyrene
>-Polystyrene can have a tendency to often be toxic. From a posting I read
>on the list a few weeks ago (I apologize to the author for not recalling
>their name) somebody had colored polystyrene figure-eights (I believe
>coloring may not be the only source of toxicity, by the way) in the bottom
>of a pot for drainage, and the Nepenthes' roots grew through them and
>subsequently the plant grew less and less healthy. Obviously small
>polystyrene balls are a smaller target for roots, but nevertheless toxicity
>from this risk in addition to any other nasties shed by the polystyrene make
>it inferior to perlite.
>-Don't encourage those polluting polystyrene companies by investing in their
>products in this case when there are much better alternatives!
>
>I hope I was of some help.
>
>Matt - TheEdge@amdyne.net
I would just like to add to this: A few years ago I grew a hardy lily in a
six-inch pot which was to be planted out in the garden after blooming (a
common practice of mine to get some early colour after a long dark Canadian
winter). When potting up I used two (and just _two_) "peanuts" of light
green styrofoam packing among other crocking material at the bottom of the
pot, figuring no harm as I had used the white peanuts before.
The lily grew normally to just under three three feet and started to bloom
with a crown of 8-10 buds on the top. The buds then started to "stunt" and
some dropped off. This had never happened to me before with these
no-brainer bulbs unless there was a cultural problem (usually uneven
watering). Suspecting a critter or a fungus attacking the bulb, I unpotted
the plant and found nothing in the soil or on/in the bulb. It had
apparently healthy roots _except_ where they had penetrated the green
styrofoam peanuts. Older roots were dead or dying while the newer roots
around the peanuts were discoloured with few root hairs. I repotted without
the peanuts in new soil and the plant lived, but stopped blooming. It took
two seasons in the garden to recover.
I have since learned that coloured styrofoam of any sort is most likely to
contain a glut of toxic chemicals, including fluoride, and the peanuts can
be decades old negating many of today's manufacturing standards. I used to
keep a large box of them, accumulated over the course of a dozen or so
years, to pack boxes sent to family in the NWT.
If they can seriously harm and stunt a tough lily, then I am sure that
sensitive CPs would quickly suffer severe effects from being in contact
with them. I no longer use any styrofoam products in any of my soil mixes.
I have used perlite, which is manufactured by heating stone until it
expands, much like popcorn, for over twenty years and consider it an
excellent soil amendment for cps. One minor point: Algae will grow on the
stuff in moist mixes when it is exposed to light. I find this to be more of
a cosmetic problem than anything else, but it could become a real problem
when used in conjunction with seed germination.
Kind Regards,
Rand
Rand Nicholson
New Brunswick
Maritime Canada, Z 5b
<writserv@nbnet.nb.ca>
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