<?php
 
add_action( 'pre_get_posts', 'wps_exclude_cat_in_grid' );
/**
 * Exclude Category from Grid
 * 
 * @author Bill Erickson
 * @author Travis Smith
 * @link http://www.billerickson.net/customize-the-wordpress-query/
 * @link http://wpsmith.net/2013/genesis/genesis-grid-loop-in-genesis-1-9/
 * @param object $query WP Query data
 *
 */
function wps_exclude_cat_in_grid( $query ) {
  
	if( $query->is_main_query() && wps_is_doing_grid_loop() ) {
		$query->set( 'cat', '-1,-2' );
	}
 
}