Can u put young plants outside in the sun at daytime and under a CFL at night inside until they are safe to be outside 24/7.
Yes, you can but be careful. Putting a baby plant into the sun can cause shock and actually do damage to it. Going back and forth between the two types of lighting may be a bit too much for it. I would keep it inside under CFLs until you can safely leave it outside at night (when warmer temps come back). And when you do finally put it outside, make sure you do it gradually so it can adjust.
Alright, would one 27 watt daylight spectrum light be good for 7 seedlings just until they're big enough cause they're reaching for the light and growing.
Yes TaxarkanaTim is right. It's best to choose between both. And in general mj doesn't like to be moved around on a daily basis (respect the schedule and do this gradually if you don't want to shock them). I never tried a hybrid grow like that but some outdoor growers here will tell you it's not a good idea (shock). Why do you want to add light at night. So it has 18 hours of "veg" time? The daylight is enough!!! I think all outdoors or all indoors is wiser.
I must disagree with some earlier answers. My experience is that MJ seedlings are perfectly capable of taking day long full sun from the moment they pop the soil. Even here in the strong Spanish sun. That is the way the plant has evolved.
Yeah with natural sun light, you won't need any lights! That's why there is indoor and outdoor grows. Try it with two plants for an experiment? Other than that, you'll do fine leaving them outside, they will get the perfect amount of strong natural light.