A friend in another forum reminded me of the possibility of using an olla (prounounced oh-ya) in potted plants to keep the moisture level continuous and available, working like drip irrigation. This ancient method of watering involves the burial of a terracotta pot in the soil next to the roots of a plant in a pot or in the ground. In a garden they are spaced according to how far the water will seep from each olla.
File comment: The photo comes from a web site called Southwest Gardener, http://www.southwestgardener.com/blogs/category/olla/
olla-771013.jpg [ 55.24 KiB | Viewed 392 times ]
Here is a blog about making your own:http://suburbanfarmonline.com/2010/08/09/make-your-own-ollas/
My potted plants suffer each summer if I don't water daily. I'm going to try this method this year, and will make a point of dropping in some BTi in each olla to keep the mosquitoes from benefiting from the water. I'll take photos and share in the blog I've been running.
I don't think this would be practical in entire gardens in North Texas, considering the cost of the pots, the fuss of putting them in, our annual rainfall levels, and the difficulty of finding them once the garden has grown large. But I can imagine some small garden zones that might benefit from this kind of watering boost.