Backpacker Magazine reveals the secrets of camping, including getting water from a cactus in the desert.
Make a solar still… Stuff a plastic bag three-quarters full with green vegetation (grass, cactus). Place it on a sunny slope with the vegetation at the top of the incline, so evaporated moisture drains to the bottom. Either way, a quart-sized bag will yield two to three tablespoons in average conditions.
That’s not a lot of water, but it’s not nothing either. Let’s hope you never have to try this minimal technique.