How long to veg. before going 12/12

[brooktrout]

I have 4 w.w. plants that are between 18" and 24", I have topped them and they are getting nice and bushy. When should I change my lighting to 12/12? I also have 1 other quick question. 1 of the plants leaves are curling down like a claw starting from the bottom of the plant and working it's way up.By doing some reading it looks like to much N, I am growing the plants in worm castings and fox farm organtic soil. I feed them 1/2 strength M.G. nursury formula 20/20/20/ and I don't feed them that much maybe once every 10 +days. How do I get the nitrogen out of the soil, the other plants are not showing this problem. I am just having a hard time believing that 1/2 strength M.G. and the few times I actually fed them would caues this problem. Flush?
Thank you for any input!

 

[fly1]

try and get some pics up of the plant with curled leaves, it sounds like overfeeding but not with the schedule you have so maybe there's some other indicators.
my plants grew double the size when i changed to 12/12 and now it's impossible to get in so at 24" i'd think about switching them other pretty soonish unless you have the space.
how long you been veging for?

 

[brooktrout]

Veging close to 2 or 2 1/2 months. Would you flush the 1 plant with the curling leaves just to be safe? Your plants doubled in size when you changed the light? Thanks for your advise.