Speed up growing? Moving plants indoors/nutes/etc.

[MikePerson]

I just started a grow of a good amount of seedlings. This is my second batch this year, the first is doing well outside as it is. I realize that its kinda late to just have seedlings so I want to try and speed up their growth to let them catch up to the first batch.

I can't have the plants indoors all the time, due to a few reasons. Over the course of the next two weeks I can bring them indoor twice, 3 days at a time. Would it be harmful for the plants to come indoors and stay under a light 24/7 and then be moved back outside? I can accept up to a 50% death rate...

Are there any nutes that will help with this?

Thanks