Gravel colour affecting germination rate?

[irisman]

Hello all,
Have to jump in and add my two cents.  Obviously the temperature of the two
possible microclimates has already ben mentioned. (assuming they share the
same light source.   I would consider the possibility that the two gravels
have differing minerals with differing solubilities.  Check a Chemistry
handbook for solubility products of iron oxiders in them, The ironstone may
well be Fe+++  (ferric) oxide or sulfide and the other, brown, an
Fe+(ferrous)  oxide  (or sulfide?) aside from the possibility of other black
compounds  e.g., manganese making a difference.

I note in passing that someone (can't check right now) noted that his
arisaemas grew well in clay, I assume with sufficient gravelly drainage so
that  they didn't rot.  I also note that looking at some of Chen Yi's
pictures that many plants grew on steep slopes, not necessarily covered in
lots of humus or leaf litter.    So far, I've got three of hers from a
shipment this December( ?), up and growing outside.  One identified as
lingyunense,  one identified as A-121, and the other, an unidentified
species I can't check right now because it's dark outside right now., and I
need to get to bed.   Will be away from this list for  about 10 days, but
hope to see interesting stuff when I get back.  So far, it's been pretty
good.   Hope the others come up and haven't croaked.     Adam Fikso, USDA
Zone 5a, Illinois.






,----- Original Message -----
From: "Jai YU" <jai1 at PRIMUS.COM.AU>
To: <ARISAEMA-L at NIC.SURFNET.NL>
Sent: Monday, May 13, 2002 8:20 AM
Subject: Re: Gravel colour affecting germination rate?


> Hi Paul
>
> Could it be that black gravel absorbs more light (heat) hence changes the
> heat dissipation characteristics of the pot especially at the top. I'm not
> sure how this will affect or indeed does anything to germination but it
> could be a factor.
>
> Jai