"Franz Heymann" wrote in message ...
"Mike Lyle" wrote in message
[...]
How does the plant know that is is over-potted?

When the newly-formed tips of its roots reach stagnant water with an
inadequate oxygen content: they can react to this by rotting.

That does not sound like overpotting at all. Surely that is overwatering
combined with lack of drainage.

The effects are much the same, yes.

What is the difference between an overpotted plant and one put in the
open
ground ab initio?

The water in the open ground moves about, dragging oxygen in, and
also, I think, helping to stop malignant organisms building up to a
dangerous concentration.

That sounds like waffle. Let's call a plant in the open ground grossly
overpotted. What then?

That sounds polite and friendly. You don't have to believe me; you did
ask me, though.

I put a very young Acer palmatus atropurpureum in a 45cm pot about ten
years
ago. It has thrived all the time, in spite of starting by being
overpotted
and now being underpotted.

Su it often works out ok, with maybe just a slowing of the ordinary
rate of growth, especially if your watering technique is right for the
plant. But one can't be certain of getting away with it.

I have handled potted plants of one kind or another for close on sixty years
now, and have yet to find out what this "overpotted" lark is about.
Frankly, it sounds to me like an old wives' tale. [Franz Heymann]

As I say, you don't have to believe me. I think I may have mentioned
that your watering technique could have had something to do with it.