And oh yeah, meant to say, tomatoes are thirsty plants! so good luck with that. If your MiL goes for non-standard indeterminate varieties (that is, notRoma or Beefsteak or any of those industrial type tomatoes) she might find that they're a bit less picky about their growing conditions - but I bet she knows that already.

We don't need to worry about water much where I am, and especially not after our high-precipitation winter - wow that was a lot of snow - but I'm contemplating building a rainbucket system to capture runoff froms the eavestroughs, just on environmental principle (plus it would be so cool!)