Try lining your terra cotta pots with plastic. Then there is mulching
on top. You might also try those water bead thing that are mixed into
the soil. They're available at garden centres or if you're hard
pressed, tear them out of cheap diapers. You can also increase the size
of pot used.

Then there is the surfacing on your roof. IMHO heat is being retained
by the roof surface, and it is 'ovening' your plants. It is like
everything in your garden was planted beside a wall. So you can look
at ways to cover the roof/floor to reduce heat retention, either with
wood walkways, fiber matting or carpet, or whatever. Or painting it
white might help.
Dora

E. Graeme Smith wrote:
Hi,

I have a rooftop container garden with a southwest exposure that keep
drying out, and I am tired of having to constantly water it. What can I do
to keep the moisture levels up, (and my time investment down)?

I am using mainly plastic containers, ( i.e. troughs, window boxes, and
pots), and a few terra cotta containers of different shapes and sizes.

My basil is doing well, (but from what I understand it is a tough plant
and it can take it). I have tried Greek basil this year and enjoyed them
more for the esthetics that the taste. They were a nice green earlier in
the summer, but have now gotten really lame. I think this is partly caused
by the containers I used and partly due to my lack of knowledge about them.

The tomatoes ALWAYS have shrivelled leaves by August not matter what I try.
My attempts at other types of plants have had mixed results. For example,
two out of the three rosemary plants have dried out, but all three are in
the same pot.

This year I cut back on the number of tomatoe plants and have stayed
mainly with cherry tomatoe varieties. I find they produce the most fruit
and the squirrls won't be doing as much damage by staling a few of them. I
don't want to nurse a nice beefstake for several months only to have the
little rodents rob me of my rewards.

My best producers have been the cucumbers. This year I tried several types
including: Lebanese, English, Straight 8, and pickling. All of them have
done well.

If anyone has suggestions-or links-as to a solution to my situation, I am
will to listen

Thanks,

E. Graeme Smith
--
Never argue with idiots, they only drag you down to their level then beat
you with experience