"Kay" wrote in message
...
In article , Franz Heymann
notfranz.
writes

"Kay" wrote in message
news
In article , Franz Heymann
notfranz.
writes


That is an urban legend. If there were any truth in it, all
plants
planted in the open ground, which is an infinite sized pot for
practical purposes, should fail.

Up to a point, Open ground is much fuller with invertebrates,
roots
of
other plants etc

True, but how would the absence of these components affect the
relative wellbeing of plants in "correctly sized" pots and those
which
are "overpotted"?

Most soil is getting continually churned over by earthworms etc. It
keeps the structure open and allows air in, and there seems to be a
general consensus that air in the soil is a Good Thing as far as
plants
are concerned.

Absence of invertebrates means soil that just sits there getting
compacted - unless it has roots pushing their way through it.

This is not scientific. It's my rationale for something I feel I
have
observed - that the soil around the edge of a pot which hasn't been
filled by its occupant is 'stale' and just Not Nice.


I have pots which have been in use with the same potting compost
for
many years. I have never noticed any undue compaction or bad
smells.
The pots which I use for growing half hardy plants like
pelargoniums
usually just have the top quarter of the compost renewed each year.
My displays are no worse than those of my neighbour, who replaces
all
his compost every year

Yeah, but those pots are fairly well stuffed, no? I reuse compost in
the
same way. If it's getting regularly disturbed by roots or humans
there's
no problem.

Maybe that is how our experiences can be reconciled.

Franz