vegetative stage...questions?

Been growing a few years, and have had great results but now trying new methods. Question : I have had my girls one month now under my sont- agro, 4 weeks to be exact. This time we are trying to maintain the plants small to increase production, as we all know a huge plant indoor can be a problem , we have had 47 plants on a terrace greenhouse type and they grew to almost 7 feet, was an ok production but we would like more. So we were told that if we kept the plants short they would dedicate all their energy in making flowers aND NOT unsmokable cellulose. I am planning in changing the light period to flowering in about a week. The girls have just reached their 5th pair of leaves but they havent risen to no more than 20 cms, but their internodal distance is short, the stem is getting huge on all individuals and the roots are clear white, I have them now in 20cm pots.
Question: should I wait till the 6th veg week or change the lights on the 5th?
Thanks to all my brothers and sisters of the INTERNATIONAL CANNABIS BROTHERHOOD....WILL upload vids and fotos of this new harvest soon....
" WHY DO YOU WANT TO SMOKE AND DRIVE WHEN YOU CAN SMOKE AND FLY"...BM

 

Hey Huarsh! Looks like ya wanna move indoors and take control . Whatcha growin in? Are ya goin hydro too? How many watts ya flowerin with? <<Just a couple q's fpr ya. When your growin indoors you have full control and can manipulate your plants the way you like. Keepem short by keepin the lights close enoughf to them so theyre comfortable yet bathed in intense light, I keep 400 watt lights 6 inches from my canope. Dont letem grow into the lights, use string to tyem down instead of raisin your lights, spreadem out too while your tyenem down. and It all depends on how much your plants strech in flower as to how long ya letem veg but I figure 6 weeks of veg is fine to initiate flowering as long as they look like theyl pop out enoughf bud sites while they streach. Youl find out how they streach by runnin a fyew sets of clones threw your system while keepin the systems conditions optimum, after a couple of runs youl see just how long to letem go in veg before theyr too big for your system to flower. Blessins!