seedlings height?

hmmmmmm....

3 weeks into an auto flower seedling, just about ready for the HPS in a day or so, looking really healthy, nice fan leaves, nice stems, nice dark green leave colouring, no signs oif problems except.... she is is only about 2 inches in height still!!!

the branches coming off her are about the same bloody size!

Been under a CFL 125 about 8 - 10 inches off her and she just seems reluctant to sprout up the way... been on an 18/6 cycle.

Is this ok, or should I be looking into some reason why she's not taking on some more height?

Apart from that, I'm quite happy, she seems to be growing, just very slowly in the vertical area!

Sounds like a healthy plant man. As long as she's putting out healthy leaves there's not really any reason to be concerned. If you wanted it to stretch a little bit you could always raise your light a little but short strong bushy plants are typically the goal so I'd just say keep up the good work and just let it grow. Especially if you're working with an indica-dominant strain (ruderalis brings on more miniature plants as well) I wouldn't worry.