How about putting ankle monitor bracelets on the stems. You know...probation misting system. Just kidding...couldn't resist.

I saw a presentation by one of the ARS NPGS experts that covered some interesting related topics the other day (I think it's about a third of the way through the video linked below). A couple of things he mentioned was:

1. A heating cable buried in sand works better for more even heat distribution than one of those heating pads.

2. An "electronic leaf" is very effective at controlling the water in varying conditions. But, the suckers are pretty pricy ($270)!

3. Cheap, plastic emitters with larger diameter outlets seemed to get clogged a lot less and work more reliably.

Keep us informed of any good info you get ahold of. I might consider stepping up to a more sophisticated set up one of these days.

Here is a link that might be useful: ARS NPGS pomegranate presentation