was Growing nerines, now clay versus plastic pots

Peter Taggart petersirises@gmail.com
Tue, 04 Oct 2011 00:43:14 PDT
I am amazed at the lack of insight into clay pot management. Our pots are
simply tools and as a carpenter may use a spoke shave for one job, he my use
a plane for another.
When I dig up potatoes I use a fork and when I mix compost I use a shovel.

A small clay pot holding a Hippeastrum or Gesneriad, standing on a
windowsill, will dry out very quickly,- so for that I use a plastic pot.
A large clay pot holding Haemanthus albifloss in clay soil, standing on a
windowsill drys slowly and is impossible to saturate, so I use a clay pot to
ensure that it doesn't rot, - plastic would be fine if it were never over
Out side I have a couple of thousand pots of assorted bulbs under glass and
in open plunges. The quickest way to kill a winter growing bulb is to water
it in a black plastic pot and leave the pot exposed to hot sun. The roots
and bulb will cook.

Properly plunged clay will behave as part of the plunge medium with an even
moisture air and nutrient flow throughout the plunge. I find this very
useful for bulbs adapted to hot dry conditions where the roots and / or
bulbs are deep down where they stay cool and moister.
On the scale of individual pots this hot surface and cool base can be
achieved with plastic long toms packed together, as Alberto describes and no
doubt Nick is achieving.

It is apparent that several people have learned how to use plastic and
failed to learn how to use clay. Their failures with clay are because they
don't use clay pots in a way that suits their own conditions and maintenance
regime. It really doesn't matter so long as their plants grow well in the
regime and pots they use. I use both to good effect, and have enough
experience to know that clay pots also have useful qualities.

The "refrigerating effect" Alberto refers to is very desirable for a lot of
bulbs I grow which go dormant when too hot. Before or after a hot day in
late autumn or spring, spraying to cool the plants down will help to
maintain growth and stop premature dormancy.
I think of this as a replacement for early morning dew, or mist, It is not a
drenching and should never be done in hot sun.
Peter (UK)

On Tue, Oct 4, 2011 at 4:29 AM, Alberto Castillo

> It is refreshing to see such an authority as Nick de Rothschild bring some
> reality to this incredibly traditional view.
> The worst effect of clay pots to certain bulbs is the refrigerating effect:
> it cools down when watered and heats as mix dries.
> This is a long list but I grow my bulb collection (and allied plants)
> comprising thousands of them, all in plastic. Not a single one in clay and
> all do perfectly well. Of course the mix in them is very well drained and
> most important drainage holes are carefully cut.

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