Green house question

I am vegging i skywalker og & diablo og indoor . My goal is to veg till they get to 18"-2' and then flower in green house . How tall will they get when fully flowered ?

All strains are a little different. For the most part they do not grow much in flower. Maybe another 10-20%. There is always the exceptions. I have know some to grow another 30+% during flower. If so just bend and tie down so they will not burn on the lights.

indica's grow .5 times it's veg height in flowering, hybrids around 2 times it's veg height and sativa's around 2.5 times it's height