>Good information about the phosphorus, thanks! I'll add that soil biodiversity is better with a pH of 7 or higher, as that is what it takes for bacteria to flourish. Bacteria are at the base of the food web, eaten by nearly every other soil-dwelling microorganism, so they are kind of important. Sure. Someone told me that adding mycorrhizae to garden soil can’t hurt, though for some plants the addition might have no effect, or it could be the wrong kind (ecto-, arbuscular, or arbutoid), or the wrong species in the case of a plant which is colonized by only one species, or the mycorrhizae could be dead on arrival. There seems to be some evidence that species dependent of ectomycorrhizae can survive under, say, manzanitas (arbutoid), but whether or not calochortus, which I assume are associated with arbuscular mycrorrhizae (the most common type) would survive in a similar situation is another story. (There’s a short paper on this subject you can download if you Google “manzanita mycorrhizae” and then “Download Emily’s synopsis...”) Bob Nold Denver, Colorado, USA _______________________________________________ pbs mailing list pbs@lists.ibiblio.org http://pacificbulbsociety.org/list.php http://pacificbulbsociety.org/pbswiki/