To tall maybe to close together not enough spacing ?

I have posted this in two other forums and had massive views but only 1 answer maybe ia am in the right place now could really use some advice or comments or even an educated guess
I am a newbie this is my third grow. I am having a problem with height. Growing these strains; Master Kush (nirvana) Fruity Juicy Chronic(Delicious Seeds) Kali(Big Bhudda)
Growing in 2 systems 1) DWC Bubbler 18 gal (6) 3.75" net cups with Canna Nutes.
2) Areoponic/NFT (Stinkbud/GH Copy) (9) 2" net cups 3 per tube with Botanicare Organic Nutes. Started 5 of each in paper towels at 80 F all popped in 48 hrs with good root showing, Put into Rapid rooters in prop tray under humid dome under 125 Watt fluro for 5 days. Put into bubbler and areo under (2) 400 watt metal halide with 6" cooltubes one on each 18/6. Lights kept at 3-5" no burn to plants. Kept lights as close as possible without burn , tons of light and room ventilation. After 21 days under Halides the girls (Feminized seeds) were between 16 - 21". At total age of 26 days from pop put in the HPS bulbs switched to 12/12 and flowering nutes. Now after 14 days of 12/12 they are all showing sex(female) the tallest one a kush is 32" and the smallest Kali is 28 ". The Kush is supposed to finish according to nirvana at 21 - 24". But the way things are going its gonna be more like 60 - 64 " by finish. So here we go i dont think it is due to not enough light or light to far away from top of canopy, these are not sativa or sativa dominant. My best guess is i planted to close together getting greedy trying to crowd to many in each unit, not enough spread between plants so they couldnt grow out to the sides so they grew up instead. I am puzzled i am trying to learn how to do this right. I am thinking in hindsight should have started flower at 12" but they would have only have been vegging for about two weeks or less is this to little vegging time ? How much space (circle around main stem ) do they need, my instinct now tells me they should of had 8 -12" around each plant am i right or wrong. I am sure some of you old pros have seen or dealt with this issue before i am trying to learn how to do it right so i can pass it forward. Any suggestions ,comments or schooling would be appreciated.
I dont really want to bend em and tye down as have had bad results in last grow

I had to super crop and put a string trellis over my aeroflo and slowly start bringing the plants down with the trellis pulling it lower and tying it off every day for 4 days. The first day they looked bad but they looked good in 24 hours and all made a full recovery harvest next weekend!Plants can triple in size in flower so a 2week veg. is ok for sea of green if this is what you are shooting for.If the lights are to far away they will stretch more. My spacing is on 7in centers for 3in cups long ways and 9in centers the other way it works well. next unit will be 9in centers even in all directions.

I have an 18 gallon bubbler with 3.75 cups as well. I know that most of them that you see have 6 cups and I started out that way also. I had major crowding issues and now run only 3...it works better for me. My space is limited and it's sounds like you may also, I go to 12/12 when they are 12 inches, my set up is not really good for anything larger. I learned the hard way, good luck.

Growing clones will help if you can support them. They retain the age of the mother plant so they can be flowered as soon as they have roots. They will still grow and stretch for a couple weeks in flower. What was your problem with LST? In aeroponics the plants grow so quick that I LST a branch 3-4 times sometimes just to keep them a little shorter and bush out more. They don't even slow down, kinda like they are saying "screw you man , I got shit to do!" LOL, good luck bud.

I think its just because of the aero/bubbler. There growth is off of soil it sounds like. A shorter veg time will help

John

how tall do they reccomend it be b4 flowering? a plant about doubles-triples in size, height included, when they start budding. So if you vegged like till 6-8 inches it would finish around the height they say.

Thanks to all for input and advice i think my systems just work to good and my spacing is to close next run im gonna decrease amount of plants and increase spacing maybe do a little topping in veg and run 3 weeks in veg or 12" - 14 " then go to flower might run the halide the first two to three weeks of 12/12 read somewhere HPS promotes more stretching than halide and most strecthing is in first two to three weeks of 12,12. Has anyone out there used Bushmaster to prevent stretching im a little leary sounds like if you use it wrong it can completely stop growth. Thanks again to all who answered. I seem to grow trees when i dont want to maybe i should just grow 4 or 5 six foot trees.