can i hang my lights vertically

[HARDDON]

It would work to an extent but you'd be much better having it horizontal as there's a much bigger surface area giving off light

I concur that horizontal lighting will give off up to an extra 30% more light. That is preferred if of course you want the light directed directly down on the canopy.

I you hang it vertically, you need to 'drop' it down between the growth shoots or between plants for the same, if not preferred effect.