spakker wrote:
[...]
Thanks for reply -I did nearly kill a fatsia japonica by omitting
drainage holes -but it has recovered - I've the B&Q type fertilizer
and maybe I should apply it more often-. Pots range upto bigger
than
half - dustbin size-tubs with rope handles. The washing - up liquid
method to wet dry soil sounds good -is the washing-up liquid
harmful?

In the tiny quantity needed to make it simply a wetting agent it
won't do any harm, and may even do a smidgen of good. Another
approach is to dump those unusably small slivers of soap in the
watering-can and leave them the this will foam less than
washing-up liquid as well as being less wasteful than just chucking
it away. It can block the spout, though. Neither is infallible, but a
bit better than plain water.

(OT sad story. I met a poet who'd found his watering-can blocked, and
on investigation discovered a dead bird jammed in the spout. The poor
thing had got into the can, and apparently tried to panic its way out
to the light it could see at the end, and got stuck. He wrote a poem
about it: that's professionalism!)

--
Mike.