try an MH bulb through 12 | 12 until you feel the stretch is subsiding and you have good bud set. buy a quality one. way tighter internodal development in my work, and I use eye hortilux hps bulbs which have more blue than most HPS. No way it can compete with what a good MH does. of course you get more useable light out of hps so switch to that in, say week 4 (when the red is less important than luminous flux) and sugar leaves can make full use of the extra light.
the intention is to either get less height but more bud sites or the same hieght as you have now but WAY more bud sites. you should also notice more pronounced root development/more root mass resulting from a quality MH bulb. If top side = bottom side (above ground mirrored below ground) you catch my drift. with more bud sites and more root mass, the yield should increase.
a veg and 4 weeks of 12|12 with MH (instead of switching to HPS right on the flip or just going the whole way through with it including veg) took me to the next level in a cabinet (horizontal) I'm trying to hit a pound of smokeable in off a 400W light. best so far after a year and a half is 12 ounces. average is 9 - 10 ounces. sog, 4" rockwool blocks flood and drain. 5" centers, adjust-a-wing medium, lumatek, 24 plants (but more mountainous/indica than your strain tho new stuff is kush and doesn't yield as well as previous hybrid)
I also am a staunch follower of lucas. strict purist is good. you can also pull some sneaky tricks borrowed from the green house industry and get your P-K a bit higher in week 1 through 3. idea is to go up from the 1400 ppm (or 1000 ppm) Lucas to, say 1600 to 1800 AND MAKE SURE IT IS MAINTAINED HIGH. keeping roots on the wetter side (while still maintaining health) and higher TDS or ppm at the appropriate time reduces stretch and works. i heard this re-greenhouse tomatoes and tried it. just get it back down after good bud set so more water is available and expansion/cell division resumes in earnest.
and i noticed a difference when i went with 36 hours of dark on the flip. like bud sites showing 6-7 days sooner (!!)
can you get something white on the whole floor? my light meter doesn't really register much difference with more upwards reflection but the plants benefit. the more blue light you can get on leaves (even underside) the better in terms of stretch. and since you grow strains with equatorial in them, you need as many advantages as you can get.
thank you for posting this journal. words cannot describe what it has done for me. i also run verticals and have problems getting small rooted cuttings to develop evenly because i go from rockwool starter plugs to hydroton.... always need a week of separation when crossing a media barrier (wet - rockwool, moist - perlite, dry - hydroton) so can now use net cups with the rockwool in perlite in mini hempy beercups till loading them in the hydroton filled vertical. I'm mostly on cannibis-world.org but this site has been HUGE for info.
peace
ps. try an MH bulb
