Date: Tue, 29 Apr 1997 13:14:15 -0700 From: Wim Leys <wim.leys@lin.vlaanderen.be> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1701$foo@default> Subject: Re: Re: perlite, vermiculite ?
Hi Niels,
> One last question on the subject: Can "leca" be used as a substitute for
> perlite or vermiculite in a cp soil mix or only in the bottom of pots to
> avoid standing water as suggested by Wim? I haven't seen perlite for sale
> in Denmark.
In Belgium I know of only one source of high grade perlite. It costs
about 100 USD for a bag of +- 100 liter. Low quality perlite contains a
lot of dust. Boy, you grasp for air if you inhale some of that dust.
I've been told it is hazardous (causing lung damage).
If you are looking for perlite in Denmark, try Yahoo or another internet
search engine, perhaps there is a store that sells it or look in your
yellow pages. I used Yahoo lately for "SuperThrive", well I guess
sometimes the spin off is better than what you were looking for (great
article about growing Nepenthes, for a Nepenthes newbie like me).
About using expanded clay as an replacement for perlite, that should
work if you can find very fine expanded clay grains or broken grains.
Some cactus and alpine plant growers use it to cover the soil of their
pots.
Hi Dave,
> > I stopped using vermiculite. My plants (Sarr, VFT, Nep, Darl, Dros) just
> > don't grew well in it.
>
> Perhaps you were using too much? I use a small amount of the
> very fine grade in the soil for Sarracenia seedlings (it's causes
> them to grow very quick), pygmea Drosera and annual Drosera species
> and Nepenthes. I have found that it really doesn't agree with VFT,
> Darlingtonia, most other Drosera. It is a must for many Pinguicula
> (Mexican, esp.)!
Nepenthes : 1/1 peat / vermiculite
Sarr, VFT, Darl, Dros : approx 6 peat / 1 sand / 2 vermiculite
> For plants with very fine roots, like Nepenthes, I add diatomaous
> (sp?) earth to the soil (about a 1/4 of the total volume). It acts
> just like perlite (it *is* the exact same chemical solid, BTW), but
> the pieces are nearly mircoscopic. On that note: Do not breath in the
> dust from it! Same goes for peatmoss or any other soil componet. <---=
> Anyway, just wet it down before mixing and don't dry out the soil after
> that, you'll kill the plant and possibly let dust into the air. It
> works much better than perlite since the individaul pieces mix right
> between the fibers in the peat moss, fluffing it up and makes it water
> retaining yet very well drained =--> but without vermiculite! Makes
> great soil for seedlings of most genus, also.
Seems diatomaous earth is more hazardous than perlite. The diatomaous
earth-particles must be about as small as the dust from perlite. This
dust gathers on the bottom of the barrel in witch the perlite with water
is stored. It forms a crust like clay. The water has to be stirred to
get it into suspension. It is used in the soil mix, to avoid having to
throw it away, but I can not say if this works better than the normal
perlite grains. My impression is not so positive, also perhaps because
this wet dust (clay) doesn't mix very well and forms clumps.
Kind regards
Wim
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