Another note on pots

Paul Tyerman
Sat, 30 Oct 2004 13:05:26 PDT
At 01:26  30/10/04, you wrote:
>      I've made a simple change to my containers that has made a 
> considerable difference on heating and drying of the soil ... I use WHITE 
> pots instead of the ubiquitous black or dark green.  The change in 
> temperature is quite noticeable, especially in the smaller 4" seed pots I use.


The one problem with white or light coloured pots in our conditions at 
least is that we get extensive algae produced inside the pot due to the 
light penetration.  It can be quite damaging to the root systems of some 
plants as it seems to bind the soil together and stop water from permeating 
the soil as well.  I have bought things in small pots that are pale 
coloured and when repotting found that the whole root ball when dropped out 
is covered in a green film, which is quite solid when trying to tease the 
roots out.  It is at least worth mentioning this for environments where the 
sun is fairly strong.

The other problem with white pots is that they do not last as long as black 
pots (this applies to any colour other than black).  The process of 
colouring (well at least here in Australia anyway) makes a plastic that 
degrades at a quicker rate, so I find ithat n our conditions smaller 
non-black pots tend to start becoming brittle within 3 years or so 
(sometimes quicker), whereas black pots last for at least twice that.  This 
is not my imagination as I have talked to suppliers about this and there is 
scientific backing for this.  I know a plant wholesaler near here who will 
not use anything but black pots, as they have less than half the life of 
the black pots in their conditions.... which tends to add up when repotting 
and reusing pots as often as wholesalers do.

I agree with your temperature comments though..... it is just that you have 
to weigh up the pros and cons of the other side effects of the coloured pots.


Paul Tyerman
Canberra, Australia.  USDA equivalent - Zone 8/9

Growing.... Galanthus, Erythroniums, Fritillarias, Trilliums, Cyclamen, 
Crocus, Cyrtanthus, Oxalis, Liliums, Hellebores, Aroids, Irises plus just 
about anything else that doesn't move!!!!!

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