Should i start to flower?...

Hi this is my first time grow, had no real probs jus yet.
Im growing from soil using a 600W HPS lamp, no nutes jus licquid oxy every other day (i recomend this as i seen i great improvement when i started using liquid oxygen)
anyway my plants are regular bagseed so not to sure on when to start my 12/12 light cycle any advice is welcome, and any comments!!

thanks a BUD!
Hydro

just know that your plants will at least double in height when you start flowering. base when you start flowering on that and how much room you have.

thanks il keep that in mind

if you showed or told height restrction i could tell you weather to 12/12 or not

i could technicaly grow to the ceiling (bout 2.5metres), but would like to keep them to around 1metre 1.5metre max!