Yeah, they really are amazingly water efficient. My daughter has one on her south-facing deck in Salt Lake City and grew tomatoes and cucumbers in it last summer. They had weeks of 100+ temperatures and humidity in the single digits.
I meant to add, George there really are no "drought tolerant" vegetables. As Ken says, vegetables need lots of water regularly in order to produce for you. If you let them dry out at all, they will either just stop producing, make dry woody produce, or bolt to seed. Prickly Pear cactus do bear nice fruit on a drought tolerant plant, though. Our neighbor in Salt Lake used to give jars of Prickly Pear jelly as a holiday gift.
Most of the Mediterranean herbs like sage, rosemary and lavender are fairly drought tolerant due to their heritage.
Did you listen to the latest podcast that Dave and Trish did? They make great points about growing a lot of veggies, with regard to which ones give you the best yield for the space you have. This also applies to the water you have - high yield in less space also equals high yield per gallon of water used.
