Need help with matching lightcycle!!

I was wondering if anyone has had this problem.
Last year when I took my girls from the veg room and put them outside.
After a while there was a definite preflowering. I was raising the plants on a 24 hour light cycle and I think that when I put them out into a natural light cycle they started to flower.
And then went back into vegetation.
So my question is, does anyone alter there indoor light cycle to match the natural cycle before they go outside?
If so how much do you alter from 24 hours a day per day.
I was thinking maybe dropping 30 minutes every 2 or 3 days until I reach my natural cycle.
Then I can put them out side. Hopefully with no problems.
Any comments or input?
Thanks for the input.

I would do your plan by dropping the light cycle some every few days..at this point in the month the sun is only out max 13 hours so I would get them down to about 18 or 16 hrs light schedule before you move them outside. keep in mind Mj only needs 6-8 direct light to grow. The rest is ambient light that is being reflected and or just being absorbed because its bright outside, if that makes any sense ..couple beers down and trying to still make sense. End result is you want to break the 24/7 light schedule you have them on. And why run them on 24/7 ? ...18/6 gives the same result and you pay less for power...every one needs sleep even plants...I would suggest using 24/7 for clones only....IMHO

Actually I have found better growth in my veg on a 24 hr cycle. My clones are in the same room and the always on seems to keep every thing from freezing in the winter.
So does anyone have a personal story with this problem as the moral of the story.
Can I go more then 30 min per 3 day. They wont be going outside until early may so I have a little time but not much.
I seem to get a harder flower on my indoor that is vegged on 24 and then switched to a hard 12 hour flower. just my experience.
I agree about the sleep, but as I said it does keep them from freezing in the winter. In the summer I do use 18/6.
Thanks for the input so far.
Keep it coming.