> What exactly are perlite and vermiculite? How do they effect the
> soil? Do they change soil pH? Do they contribute minerals to
> the soil?
As already mentioned, these are non-organic mineral supplements.
Geologist classify vermiculite as a clay-derived mineral, but don't be
confused by this technical classification. Vermiculite is a very
flakey, airy, mica-like material that is very different than the
layman's understanding of "clay".
Horticulturally, these two minerals are used for:
1) reducing organic content of the mix for plants with
tendency towards root rotting
2) making the soil drain better
3) increasing the aeration of the mix
Some "gotchas":
1) vermiculite is slightly alkaline, and should be used only
with plants that will tolerate alkaline conditions. It is
perfect for Mexican Pings, for example.
2) With passage of time, some types of vermiculite may decompose
into dense "sludge". Using a coarse grade tends to prevent
this. If the vermiculite does collapse, it will become
a counter-productive component of your mix.
3) Perlite is generally pH neutral, but may sometimes have
harmful trace minerals. One grower I know has had Heliamphora
suddenly die when repotted in certain lots of perlite.
As with any horticultural endeavor: "Your Mileage May Vary".
A picture is worth a thousand words, but experience is worth a thousand
pictures. Drop by your local garden shop and get a $2 bag of both
substances. Try 'em out on some non-critical plants. You'll learn
alot more that could be conveyed in many pages of discussion.
-------------------------------------
> Subject: What is D. coccicaulis
>
> Has anyone ever heard of Drosera coccicaulis? I recently
> purchased a plant from "California Carnivores" marked D. coccicaulis. I
> have not been able to find any literature on this particular sundew any
> place. It is not listed in the CP Database either.
D. coccicaulis *does* appear in the database. Just make sure to
click on the button: "show all matching entries, including synonyms
and common names". Otherwise the search engine will not find it,
as "D.coccicaulis" is not a valid name.
Best regards,
-- Rick Walker