On 26/10/15 01:49, David E. Ross wrote:
On 10/25/2015 12:54 PM, Hypatia Nachshon wrote:

I need to repot a young pomegranate tree; planter cracked. Not ready
to put it in the ground yet; maybe not at all; depends on redesign of
area.

Very large planters are pricey, so wondered if large redwood planter
would do the trick. Any experience out there?

TIA

HB

As I recall, you are in southern California. Avoid plastic pots. They
will get hot in the sun and cook the pomegranate's roots. Clay pots and
redwood tubs (if you can find them) will stay cool as long as the
potting mix inside remains moist.

That is an often-repeated "fact" but I wonder if it is a bit too
simplistic. If you have standard terracotta-coloured pots I would think
it is true. But what if you have white plastic pots and dark-coloured
clay pots? I would bet on the white plastic remaining cooler than the
dark clay. Then, of course, you have the cooling effect of water
evaporating through the clay. That's not true of glazed clay pots,
however, where evaporation can't occur. On the other hand, you are more
likely to find a plant drying out in an unglazed clay pot than a plastic
one. Then there is the consideration of what you want in winter. A dark
plastic pot which heats up quickly may be preferable to a light-coloured
clay one which keeps the roots cold!

I would think that it might depend on the type of plant you are growing.
Cacti and other succulents won't mind their roots heating up or being
dry for extended periods. Most normal plants won't like hot or dry roots.

If the OP intends moving the plants around then large clay containers
will be very heavy. I would go for white plastic, or terracotta plastic
painted white.

Some interesting comments at ger.com/article/10.1007%2FBF01372847

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Jeff