On 4 Oct 2009, at 10:18, Jane McGary wrote: > I live where horticultural pumice is readily available. As it is generally in the Pacific Northwest. Here in BC, all we can get is pumice from Keefer's Greenhouses in Vancouver, in plastic bags and costing the earth considering what a plentiful material it is. The pumice they sell is a dead gray-white that I find visually unattractive. I have to wash it over fly screen to get rid of the fines, which I have in the past found will form a layer at the bottom of a pot and totally block drainage. In Washington state, Verkist orchid nursery outside Bellingham sells (or used to sell) both washed and unwashed pumice, the former in your choice of sizes. It's been many years since I was there, but the price was quite reasonable. The pumice they sold was a warm ocher yellow, very attractive. I don't use pumice for my bulbs, perhaps because it's really over priced, but I do use it for high alpines, many of which seem to very much enjoy it. I have a large pot of Weldenia candida that has pretensions of becoming a cabbage! > Our NARGS chapter in Portland recently heard a talk by Truls Jensen > of Wild Ginger Farm nursery called "Fresh air," which featured his > techniques for increasing air space in container soils in order to > grow xeric plants successfully. Undoubtedly many of the subscribers to the PBS mailing list have at one point or another heard Phil Pearson and Steve Doonan's dog and pony presentation on the importance of air in one's potting mixes. The importance of the roots having plenty of air seems to be rather poorly appreciated, but Florence Bellis in her "Gardening and Beyond", published 20 years or so ago, urged gardeners to fork over their beds every spring to improve aeration. The principle is nothing new. -- Rodger Whitlock Victoria, British Columbia, Canada Maritime Zone 8, a cool Mediterranean climate on beautiful Vancouver Island http://maps.google.ca/maps/…