Jane McGary janemcgary@earthlink.net
Tue, 02 Jul 2013 13:51:18 PDT
I have always preferred unwashed pumice with fines for my bulb and 
alpine mixes. In addition to retaining moisture, the fines also 
release a significant amount of nutrient and help to balance the pH 
of what would otherwise be a pretty acidic soil, given what is 
available to us here.

Washed pumice is also available here but it's mostly used in 
bark-based coarse potting mixes for growing conifers and other woody plants.

Jane McGary
Portland, Oregon

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