Rodger wrote,Another suggestion derived from a web site you might be able
>to unearth again: a tecophilaea grower in the LA area swears by
>decomposed granite as a soil mix ingredient for tecophilaeas.
>His opinion is that the potassium it slowly releases is
>beneficial. These days, my own t's go into a 50-50 combination
>of my usual mix plus fine granite sand ("canary grit"). So far,
>so good.
Decomposed granite (the soil at my brother's place in the coastal hills of
the Monterey Peninsula) has a great deal of fines in it; it sets up like
concrete when dry, but immediately becomes friable when moist (it's famous
for mudslides -- one went through his neighbor's living room). I'm sure
there are plenty of available nutrients in it, and many native bulbs grow
in it. This is why I like using "pit run" unwashed sand (mostly basaltic,
here) and unwashed pumice -- I think the fines make the nutrients more
available.
Jane McGary
Northwestern Oregon, USA