Barb wrote:
I have lots of plants around my house - I haven't the faintest idea what
most of them are! - including a 3ft palm-tree thing - all of which are doing
very well. I'm obviously "good" with houseplants.

However, I'm going away for nearly four weeks in June and no longer have
someone I can ask to pop in and water them once/twice a week.

Some of them have been with me for a while, and I'm quite attached to them -
is it feasible to put them outside for the duration? On the basis that the
outside temperature is in the teens during June?

I don't know where you live, Barb but in some parts of UK there are
still frosts in June.

Presumably I should put them where they are shaded from direct sun, but get
the rain, and perhaps in standing water so they don't dry out.

Standing water is a bad idea for almost all plants.
I wonder if your local paper or newsagents/post office would have ads
from someone who offers to house sit while people are away. Quite a
lot of people do this sort of thing - some advertise in e.g. parish
magazines, too. Obviously, you'd have to take up references but
something of that kind might work for you. OR, do you have a friendly
nursery or florist nearby that would be willing to take them for you in
exchange for a small fee or a bottle of hooch? We've over-wintered
things like Aloes and Agaves for someone who collected them but had no
conservatory. Her 'payment' was her choice - one day a week's work
in the nursery for a few weeks in spring. She liked working here and
she learned a lot, too.
I imagine you're arranging for the post office to hold on to/forward
your mail but if not, how about the person who is picking that up,
checking the plants, too?
--
Sacha
www.hillhousenursery.co.uk
South Devon