My first grow, speaker grow box

[Opie Yutts]

If i put a light strip on the side wouldnt that make the plants grow to the sides instead of vertical growth since plants grow towards the light?

Somewhat yes, especially more toward the bottom after the canopy above has shaded it from the HPS above. Since there is a 150W HPS at the top, the plants will want to grow toward that since it will be the brightest light, but once it's shaded they'll go for the side lighting. Another reason for a training screen.