yup, thats what you want, good n tight internodes. that 600w mh is going to do you wonders. i tried checkin out ur journal to see your plan / setup, but there are no entries. you should post some pics o this thread so we can see what your workin with! how big is your soase, and what all are you usng to grow this lady? nutes, soil, etc.check out my grow journal pics and you will see my plants. i have recently changed to a 600w metal hallide bulb which seem to be stopping them from stretching but keeping the nodes very close together.
true true. my last baby was LSTd and about 5" tall on all 9 arms before flower. once i swiched to 12/12, i got about 18" or more, so ya acount for the stretch!What strain are you growing? A sativa will stretch far more than an indica strain. Measure the distance from your soil to 12" below your light when it is raised as high as it can go. This will be close to your max height for the plant. An indica will about double, a sativa will at least triple, and a hybrid will usually be somewhere in between.
If it is a bag seed just assume it will be about 2 1/2 times larger/taller.