On Sunday, 4 March 2012 18:05:32 UTC, AL_n wrote:
"Charlie Pridham" wrote

The main reason is the lack of air and water circulation in pots
compared with the open ground so any compost not being actively used
by the root system has the chance to become stagnant which in turn can
start root rots, its true not every plant will be badly effected but
unless I know to the contrary I try and use a pot that allows my
fingers down the side but no more.

Thanks. Would you use the same procedure outdoors with plants inteded to
end up in a large planter/container?

Al

Charlie's right and yes I'd use similar rules for outdoor containers (though I usually avoid growing plants in containers anyway) but as the containers get bigger the increments have to increase a little accordingly.

Rod