i switched to 12/12 like 2 weeks ago...one of my ladies seems to have entered flowering, but the other two havent...would it be ok to switch back with 16/8 until i see the pre flowers on the other two? and would the stress it cause be worth it?
Yes I believe it's o.k. to go back to 16/8. Many people who grow from seeds do this to determine the plants sex before continuing vegetation for various reasons.
don't do it! they'll have to revert back to veg, and then back to flower again. you will add weeks to your grow!
I would recommend against doing this. Like Growbot said it will add weeks to your grow and would add some stress to the plant... If i may ask why would you be doing this. Are looking for bigger plants? Because your plants will double and triple in size in flowering phase usually. A little more info will help us help you !!!
I triple that. Stringer is correct that it is OK, in that it most likely would not harm the plant, but it is far from ideal and will delay your grow. What you essentially would be doing is reversing course a couple of times on hormonal reactions that rely on sustaining a momentum, and it takes a while to slow down and then get going in the reverse direction, finally building up momentum in that direction, and then the plug gets pulled again and they have to slow down and reverse again. From a hormonal standpoint, the plant spends a lot of time standing still, so the added time to your grow is not productive growth just stagnation (plus expenses for electricity, nutes, etc during this time). Total loss of momentum hormonally.