On 2011-07-04 17:08:20 +0100, Jack said:

Thanks for all the replies - v helpful.

Does it make a difference if the roots are short, near the top of the pot
(ie seedlings or cuttings)?

Best to drip water automatically into the top of the pots. Maybe not
worth it for one short holiday a year but if automatic watering appeals
all summer long then you might want to invest in a timer for the
outside tap and a drip irrigation system. Take a look at the various
options:
http://www.garden4less.co.uk/product...wc4QoduUhS YA

I

use the Aquapod system all year round to water plants in my front porch
and it is by far the easiest auto irrigation system to set up. Without
it, or similar, I would ban plants from the porch. And without
automatic watering of my raised veg beds, I would stop growing
vegetables. Move with the times - these systems are economical with
water and there's even a tap timer which comes with a ground probe that
automatically suspends any pre-set watering program if sufficient
rainfall is detected.