preventing rain water from vents???

how can i do this? , i will be fixing a vent grill for air to flow in . the vent pipe is going above out to the roof , the vent grill is going flat on the roof looking upwards,

how can i go about doing this , i dont want rain water to fall through the vent and pipe and into the grow room,

can anyone advice me ongetting this write the first time.?

what can i do ,
i dont want to use a pipe that bends coz i dont want anything sticking out of the building where it can be seen, id rather have a flat grill ,
so it dont look like the building is being used.

what else could i do?

buy a passive roof vent at menards/home depot. your roof should have them already. why not just vent to the attic, itll make its way outside.

what kind of venting do you have in your attic? out the roof i mean, if its the small squareish ones just attach a round collar and run some flex duct. or like he^ said just vent into your attic it should already be vented.