On Sat, 11 May 2013 00:13:24 +0200, kay wrote:

No, water does not "sit above gravel" in pots. Physics is not mocked.
.


Water does jumping jacks on gravel while laughing heinously.

I think what they're trying to say is that water doesn't drain until the
soil is saturated; until that point pretty well all the water is in the
soil (ie above the gravel). Just as if you put a damp sponge on top of a
layer of gravel, it would stay damp, and wouldn't drain all its water
down into the gravel. The gravel wouldn't get appreciably wet until the
sponge was sopping wet and the water started falling out of it. So all
you're doing by adding a layer of gravel is making the pot smaller.

I had a very good article exploring water movement across soil
architecture boundaries, (e.g. small to large particle size), but can't
find it.

The famous Dr. Linda gives lots of excellent advice, but it should also
be remembered that she gardens in a remarkably fertile and clement place,
the US Pacific NW. For example she says we should never amend soil at
planting time, but if I followed that advice I would have hardly a shrub
in the garden. (I have to amend and mound plant, otherwise everything
gets wet feet in winter and cant establish).

-E

--
Gardening in Lower Normandy