pumice and supplies

ConroeJoe@aol.com ConroeJoe@aol.com
Mon, 07 Feb 2005 15:36:19 PST
In a message dated 2/7/2005 11:03:32 AM Central Standard Time, pbs- Gilbert 
Nancy L Contr 9 CES/CEC <Nancy.Gilbert@beale.af.mil> writes:

> Joe,
> Where do you live?

Hi Nancy G.,  

I live in Conroe, TX, about 20 miles north of Bush Intl. Airport in Houston, 
TX.  No volcanoes here and not much pumice.  However, we do have scoria (lava 
rock).  It is sold as a mulch for use in small areas.  

I see your email address has "af.mil."  I used to work for the AF in San 
Antonio when I was on sabbatic a few years ago.  A great place to grow many bulbs. 
 But, they don't have much in the way of pumice either.  

I get a good enough effect with perlite, or heydite (turface, dry stall).  I 
use scoria for large pots (lava rock).  The reason for trying to find pumice 
is the (faint) hope it might be less expensive than scoria.  But, I'm beginning 
to think that is unlikely.  Both materials provide air pockets in the soil.  
I find that they are essential (or their effect) for xeric plants that I grow 

We have so much rain, that good drainage does not seem to be enough for cacti 
and xeric bulbs, especially when coupled with hot, humid, wet summers.  I 
find that air pockets in potting soils is beneficial.  I don't know if fungi grow 
less, or if roots survive better, or what.  But, materials that add air 
pockets to my soils are very helpful for most xeric plants, hence I like pumice or 

I can grow (some) New Mexico cacti outdoors if they are in 90% mineral soils 
(even 100%) if I provide about 1/3 scoria, and 1/3 perlite.  The balance can 
be coarse sand, gravel, or anything mineral.  

I'm trying some desert bulbs in such mixes and finding that some bulbs cannot 
be fooled as easily as cacti.  Some desert bulbs insist upon a dry 
period--air in the soil or not.  


Conroe Joe
Raining, about 65 F today, cloudy but not too cold.  Rain forecast off and on 
for the entire week.  

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