When should I flower?

I have 48" of vertical space 18"x18" square....my pot is 10" deep...plant is 13" right now....at what height should I start 12/12 cycle?

20 or mostly 25" imo.. but wait for other opinions

id say do it around 20 give or take maybe 18 depending on the strain if its a sativa you would probably want to start it a bit earlier indica you could wait a bit
kinda up to you

im not sure of the strain...just sum good bagseed...this is the plant i started with https://www.rollitup.org/general-marijuana-growing/111836-pics-sum-reggo-bagseed-slightly.html ...harvested...revegged.....im guessing sativa dominant?

Wait, I'm a tad confused... You have 48" - 10"(pot) = 38" of space or 58" - 10" = 48"?

That looks pretty indica-ish (really wide fan leaves, not very tall, and yes, I did notice it was bent). In that case, wait for it to reach max 15" (if you only have 38") or max 19" (if it's 48").

Indicas tend to double their height in flowering. Seeing that this is not a pure indica, but pretty dominant, it's height may grow 2.5 times.

thanx...yes it is bent because b4 i revegged i had it lst'd big time for the 1st harvest but i cut all the tie down off so its almost straight now...i have 48" total so minus the 10" i have 38"....seems to be growing an inch a day now or more some days...will post pics soon...thanx