how long till flower?

Hello....I just switched over from soil grow to hydro. I have a 30"x30" box with approx 40" of height for growing. I am using a flood & drain system. I am growing Strawberry Haze from Green house.

My question is when should I put them to flower to avoid them getting too tall? I typically prune twice throughout the veg state. Things grew a lot slower in the soil, so I dont know when I can do this.

Any help is appreciated.

If they have alternating nodes, you're good to go. :)