Quote Originally Posted by klondike_bar
you definitely want just instant switch to cause plant panik.
^^^ :tin foil hat: ^^^
Whatever.

You can do 24h darkness, up to 3 days actually but it's not common or necessary, or you can just decide when you want 'night' and 'day' to be, and stick everything on a timer.

I'm glad the plants perked back up.

Are you flowering under those same lights, or different ones?
If you are going to use tubes, expect to be string-training to keep them short, be certain you have the correct bulbs (all in the 'indoor lighting' section what wavelength you want), and you'll want to add another couple fixtures.

But you know a HPS is better... A cheap 400HPS is under $150 from Inside Sun last time I checked. You want to get going on the HPS no more than 2-3 weeks after you turn the lights back and stretch slows.

Final check: Have you pinched them, and if so, was it at least 2 weeks ago? The recovery time is crucial so as not to lose yield.