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