In article , Franz Heymann notfranz.
writes

"Martin Brown" wrote in message
...

I grow cacti and water them like normal house plants in mid-summer
but
they are planted in a very free draining grit with a small amount of
compost so they dry out between waterings.

That is good practice for growing cacti.. So how does that affect my
argument about the relative sizes of the plant and its pot?

Sometimes I have a cactus that is not happy, and when I tip it out of
its pot, I find that it has a poor root system. I find repotting into a
much smaller pot is more effective in encouraging growth than repotting
into the same pot. I put it down to lack of invertebrates etc in compost
and pot. It could be disease in the original pot, but I think not a)
because the most likely is root mealy bug and I check for that b) if
disease were there, the plant would carry it into the new pot.


I suspect you are somewhat meagre with the watering.

The right adjectives would be "lazy" and "irregular", not "meagre".
{:-))


Where I live at the moment I am having to tip water out of trays
under
pots containing small trees.
I am supposed to be watering them for a
neighbour but we had 100mm of rain in the last two days!

What on earth are these trays doing under the pots?

You need to ask that? ;-) "lazy" and "irregular" watering means that the
soil dries out, and it's extremely difficult to wet it again. So a tray
under the pot catches the water as it comes through and allows the soil
to soak it up at leisure

--
Kay
"Do not insult the crocodile until you have crossed the river"

In message , Franz Heymann
writes

"Martin Brown" wrote in message
...
In message , Franz Heymann
writes

"Mike Lyle" wrote in message
. com...


that any water you give will immediately go to the plant, rather
than
hang about going stagnant. (Some people, in this group notably
Franz,
ignore this rule without ill effect; but they have a watering
regime
to suit.)

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.

That isn't true though. The ground has usually has pretty good
drainage.
A plant stuck in a pot has to rely on all the extra water escaping
from
a small hole in the bottom of the pot.

My pots all do have adequate drainage holes in the bottom, and I have
never noticed any waterlogging in them.
You are not addressing my point, which was that all this talk of
overpotting a small plant has no basis..

But it does. If you over pot an orchid for example you will *never* get
flowers until the plant grows sufficiently to become completely pot
bound again. Chances are that it will go off its roots first and die
horribly if it is over potted.

Block the hole and you have
stagnant water and few living things can tolerate HS (it is more
poisonous than HCN).

I was not discussing growing a plant in an undrained pot. {:-((
If you look back, you will see that my argument is concerned with the
old wives' tale that putting a small plant in too large a pot is bad
for it. I stick to my contention that that is nonsense.

It isn't though. It is not really any different to the recommendation
not to use stale potting medium left over from last year. Sometimes old
compost even smells really bad if water has got in and its become
anaerobic.

Once there are roots taking up nutrients and water the soil is fairly
well behaved in a pot. But without some active roots in it there is a
real risk that excess compost will become inhospitable to root growth
before any roots actually reach it.

I grow cacti and water them like normal house plants in mid-summer
but
they are planted in a very free draining grit with a small amount of
compost so they dry out between waterings.

That is good practice for growing cacti.. So how does that affect my
argument about the relative sizes of the plant and its pot?

Over pot a cactus in cultivation and it will likely die.

I planted a very young Acer palmatum atropurpureum directly in a 45
cm
pot about eight years ago and have never repotted it. It thrives.

I suspect you are somewhat meagre with the watering.

The right adjectives would be "lazy" and "irregular", not "meagre".
{:-))

Most things will survive being allowed to dry out and then watered
again.

Most Japanese acers grow on mountainsides and expect to be dry at
the
roots from time to time.

Where I live at the moment I am having to tip water out of trays
under
pots containing small trees.
I am supposed to be watering them for a
neighbour but we had 100mm of rain in the last two days!

What on earth are these trays doing under the pots? Why don't you
suggest to the neighbour that they are probably doing more harm than
good? Pots are supposed to drain off excess water freely. Mine stand
on open paving, on detachable feet, to raise them above the surface.

Normally it would allow them to survive without watering for a few days
at a time whilst they are away. But given the recent heavy tropical
rainstorms up here in N Yorks it has been a pretty odd summer.

Regards,
--
Martin Brown

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

"Martin Brown" wrote in message
...

I grow cacti and water them like normal house plants in
mid-summer
but
they are planted in a very free draining grit with a small amount
of
compost so they dry out between waterings.

That is good practice for growing cacti.. So how does that affect
my
argument about the relative sizes of the plant and its pot?

Sometimes I have a cactus that is not happy, and when I tip it out
of
its pot, I find that it has a poor root system. I find repotting
into a
much smaller pot is more effective in encouraging growth than
repotting
into the same pot. I put it down to lack of invertebrates etc in
compost
and pot. It could be disease in the original pot, but I think not a)
because the most likely is root mealy bug and I check for that b) if
disease were there, the plant would carry it into the new pot.


I suspect you are somewhat meagre with the watering.

The right adjectives would be "lazy" and "irregular", not "meagre".
{:-))


Where I live at the moment I am having to tip water out of trays
under
pots containing small trees.
I am supposed to be watering them for a
neighbour but we had 100mm of rain in the last two days!

What on earth are these trays doing under the pots?

You need to ask that? ;-) "lazy" and "irregular" watering means that
the
soil dries out, and it's extremely difficult to wet it again. So a
tray
under the pot catches the water as it comes through and allows the
soil
to soak it up at leisure

I have never had trays under our outdoor pots, only in the case of
small indoor pots on a window sill, and I have never had serious
watering problems. On the odd occasion when a pot has become bone
dry, I have put a plastic bottle with a *very* small puncture in its
bottom, filled with water, on the compost, so that it could leak water
into the pot over a period of an hour or so. That has always coped
with getting the compost damp again.

Franz

"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

In article , Franz Heymann
writes

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

The right adjectives would be "lazy" and "irregular", not "meagre".

What on earth are these trays doing under the pots?

You need to ask that? ;-) "lazy" and "irregular" watering means that
the
soil dries out, and it's extremely difficult to wet it again. So a
tray
under the pot catches the water as it comes through and allows the
soil
to soak it up at leisure

I have never had trays under our outdoor pots, only in the case of
small indoor pots on a window sill, and I have never had serious
watering problems. On the odd occasion when a pot has become bone
dry, I have put a plastic bottle with a *very* small puncture in its
bottom, filled with water, on the compost, so that it could leak water
into the pot over a period of an hour or so. That has always coped
with getting the compost damp again.

I don't think you're doing 'lazy' and 'irregular' properly!
--
Kay
"Do not insult the crocodile until you have crossed the river"

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

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

The right adjectives would be "lazy" and "irregular", not
"meagre".

What on earth are these trays doing under the pots?

You need to ask that? ;-) "lazy" and "irregular" watering means
that
the
soil dries out, and it's extremely difficult to wet it again. So
a
tray
under the pot catches the water as it comes through and allows
the
soil
to soak it up at leisure

I have never had trays under our outdoor pots, only in the case of
small indoor pots on a window sill, and I have never had serious
watering problems. On the odd occasion when a pot has become bone
dry, I have put a plastic bottle with a *very* small puncture in
its
bottom, filled with water, on the compost, so that it could leak
water
into the pot over a period of an hour or so. That has always coped
with getting the compost damp again.

I don't think you're doing 'lazy' and 'irregular' properly!

Yes I am. {:-))

Franz

"Martin Brown" wrote in message
...
In message , Franz Heymann
writes

"Martin Brown" wrote in message
...
In message , Franz Heymann
writes

"Mike Lyle" wrote in message
. com...


that any water you give will immediately go to the plant,
rather
than
hang about going stagnant. (Some people, in this group notably
Franz,
ignore this rule without ill effect; but they have a watering
regime
to suit.)

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.

That isn't true though. The ground has usually has pretty good
drainage.
A plant stuck in a pot has to rely on all the extra water
escaping
from
a small hole in the bottom of the pot.

My pots all do have adequate drainage holes in the bottom, and I
have
never noticed any waterlogging in them.
You are not addressing my point, which was that all this talk of
overpotting a small plant has no basis..

But it does. If you over pot an orchid for example you will *never*
get
flowers until the plant grows sufficiently to become completely pot
bound again. Chances are that it will go off its roots first and die
horribly if it is over potted.

Until reading your posting, I knew essentially nothing about orchids.


Block the hole and you have
stagnant water and few living things can tolerate HS (it is more
poisonous than HCN).

I was not discussing growing a plant in an undrained pot. {:-((
If you look back, you will see that my argument is concerned with
the
old wives' tale that putting a small plant in too large a pot is
bad
for it. I stick to my contention that that is nonsense.

It isn't though. It is not really any different to the
recommendation
not to use stale potting medium left over from last year.

I do so regularly for around 50 years and have never experienced
problems with it.

Sometimes old
compost even smells really bad if water has got in and its become
anaerobic.

That would be compost which needs a period of recuperation before
being reused.

Once there are roots taking up nutrients and water the soil is
fairly
well behaved in a pot. But without some active roots in it there is
a
real risk that excess compost will become inhospitable to root
growth
before any roots actually reach it.

Our experiences differ.

I grow cacti and water them like normal house plants in
mid-summer
but
they are planted in a very free draining grit with a small amount
of
compost so they dry out between waterings.

That is good practice for growing cacti.. So how does that affect
my
argument about the relative sizes of the plant and its pot?

Over pot a cactus in cultivation and it will likely die.

I don't lnow enough about cacti to comment other than asking whether
you are not actually meaning to refer to overwatering than to
overpotting.

[snip]

Franz