arilate irises was bulb rant
penstemon (Sat, 15 Nov 2014 15:50:07 PST)

quick drying which other climates experience. In Britain we can experience
Spring, Summer, Autumn, and Winter in a 24 hour period.

And I bet that this requirement has been misappropriated for cultivation
techniques in semi-arid and arid environments. (No, I don't bet; I know it
has.)

Here's the Deno quote, from Seed Germination, Theory and Practice.
"It is appropriate hereto clarify one of the most pernicious misconceptions
in the
horticultural literature, namely the subject of drainage. Growing roots are
actively
consuming oxygen. It is easy for them to be asphyxiated if the oxygen
pressure is
reduced below the 0.2 atmospheres that is present in the air. The
susceptibility varies
in different species. This subject is misunderstood to an incredible degree
in the
horticulture literature. The word drainage is like a drumbeat punctuating
every
paragraph. In fact a plant cannot possible care whether water drains fast or
slow over
the roots. What is critical is the supply or more precisely the pressure of
oxygen. The
word drainage should be crossed out throughout the horticultural literature
and
replaced by the word aeration. The misunderstanding arose because media that
drain well usually are porous with 10-30% free air space so that they remain
aerobic.
What has happened in the horticultural literature is that an aeration
requirement
became misinterpreted as a drainage requirement. It can be added that if
drainage
were essential, plants could never be grown by hydroponics."

Bob