growing with the light on the side?

for a few months now i have been growin in a 3 foot attic. theres a 400W HPS. the catch is its sideways and i can only have light on half the plant at a time. the room is panted flat white for reflectivity. any one know what will happen plants look health sence i introduced HPS but im wondering if its worth trying a better strand. everything is vented and cool air circulation is not a problem. do the plants "HAVE" to have the light on TOP?? help theres photos on my page of setup.

No plants don't have to have a light on top, they can pretty much adjust to light coming from about every angle. I'm sure you see your plants leaning towards the light, turning its leaves, in order to allow the light to hit as much leaf-surface as possible. Just make sure you are rotating the plants (I prolly would every day or two) But your plants look like they're doing well to me

Cool. I have been rotating them every complete light cycle they are turning but the main stalk grows stright. Also does ne one know if you turn a plant sideways y the crown of the plant keeps growing up even if the light scorce is on the side???

yes all ways up. But you can force it "ever os gentley" to do what ever you want.