Ok, I jumped the gun. I put my tomatoes in their barrels a few weeks ago. I live in Northern California, zone 9 and they seem to be growing well with the 'walls o water'
You know, those things you fill with water that act as little greenhouses. I know that the temp has not gone below freezing, but my question is, will the low temps that they have been exposed to (45) affect their production later? Help!

bump

if production went down why would any one use them.

I don't know the answer to this one, but my best guess is that it would not. It seems like the walls o' water work much like a miniature cold frame, and putting plants in a cold frame doesn't make them weaker. In fact, I think it actually makes them stronger.

As for whether people would use them if they caused problems--well, lots of people buy and use products that are bad for them and their plants. That's why we have to call ourselves "organic" gardeners--because there is such a thing as a "conventional" gardener, who pays a lot of money for chemicals that create short-term gains only to cause long-term problems.

45 degrees should be no problem for a tomato, especially with a properly positioned wall o water around it. I'm conducting an experiment this year to see how well they work. I put a tomato in my zone 6 garden about 2 weeks ago with a wall o water and some plastic down to warm the ground. It's still healthy so far.

Wall o waters work well.