Modified from website
If you look up online, it will tell you herbs should be dried at like 115 in the dehydrator. That's insanity. I ran it at 165 and it worked much better. I don't particularly like the dehydrator for this, though, as mine has wire racks and so the small herbs were falling through.
I use the oven at the lowest setting (mine is 170) for an hour (I do 30 minute increments) in sheet pans. Much better. I do three racks at a time.