Im going crazy! I swore i read something in ECM mag that a sub panel in a detttached garage must have a separate ground rod . Is this true or im i mistaken?

Yes that is correct, take a look at 225.30 through 225.40 for all the requirements that you will need to follow for a detached garage panel.

Bob,

I read on another web site that it is also useful in case of lightning. You want the lightning to disapate in the earth by the garage in stead of trying to get back to the main house.

Thanks fellas . I knew i read something about that