first time

hey all.wanna ask a couple of question,my plants are coming on 4 weeks in about 3 days or so.there really growing now.the stems are getting really fat.leaves are nice and green.PH is at a constant 7.0 which ain't worth fussing over.everything seems to be going ok,my wonderwoman clone has rooted well so happy days.but in terms of getting a couple of ounces off each plant when should i start the flowering stage? the plants will still grower taller right? and my 200w cfl is blue/white spetrum, should i at least get a warm white/red 200wcfl specrum bulb 4 flowering?can't afford an mh or hps set up just yet...

Your replies are much appreciated.
Thankyou

I would flower now.

how much taller will they grow for a 4 week flowering period? in inches?

The actual amount of "stretch" could be reduced with more internodal growth by using a red spectrum and a blue spectrum, with more emphasis on the red, during flowering. However, if you're looking for yield, I'd suggest doing secodary budding. This is where you, about 4 weeks into flowering, force the plants back into vegetative growth by switching to a 24/0 light cycle, and keeping it for another 4-5 weeks, then switching back into flowering with 12/12 schedule for aother 4 weeks. This effectively increases the yield, I've read, by approximately 25%. (Info summarized from "Cannabis Cultivation" by Mel Thomas.)