What's the lowest wattage you can keep a mom under?

I'm curious, if wanting to keep electricity costs and heat way down, what's the lowest wattage you can keep a mom under?

I plan to have a mom in a box that just keeps her going, as opposed to having a big ongoing veg tent with a mom in. The idea is that instead of a perpetual grow, which is unnecessary for my needs, I will do a grow periodically, but want to clone a particular strain that I like. Periodically I will take a clone and fire up the MH bulb and ballast in my tent.

I should also point out that it is near damn impossible to get daylight colour CFL bulbs, so I would have to have the lady under 2700k CFLs. I hope this won't make too much of a difference as I am not wanting aggressive growth, but I worry - will such low wattage and warm temperature bulbs just make her stretch uncontrollably?

What's the best I should aim for here?

Hey dude I've kept mums under 4 2' T5's and they are like 24w a bulb, and daylight. This is a perfect light, low energy, low heat and the growth is beautiful.

If your mum does stretch under your cfl just clone her again and get rid of original when roots come through

Aha yes of course I hadn't even thought of the fact I can just re-clone over and over as she gets too big.

100W is a little more than I was hoping to use, is that really the minimum I can get away with?

I mean, I don't want to use so little as to do any harm to the plant, but if I could get away with say 60W on 18/6 that would be great.

What do you think?