add-based-on-row-number.php

<?php
/**
 * Add a special class to the 2nd row of Caldera Forms grid layout
 */
add_action( 'caldera_forms_grid_row_class', function($rowClass, $row ){
  //change to your desired row number here
	if( 2 == $row ){
		$rowClass .= ' taco';
	}

	return $rowClass;

}, 10, 2 );

add-to-all-rows-of-form.php

<?php
/**
 * Add a special class for all rows of Caldera Forms grid layout, for a specific field
 */
add_action( 'caldera_forms_grid_row_class', function($rowClass, $row, $config ){
	//Change your field ID here
	if( 'cf12345' == $config[ 'form_id' ] ){
		$rowClass .= ' taco';
	}

	return $rowClass;

}, 10, 3 );

caldera_forms_grid_row_id.php

<?php
/**
 * Change the formatting of row ID for Caldera Forms grid layout
 */
add_action( 'caldera_forms_grid_row_id', function($rowID, $row ){
	$rowID = 'caldera-taco-' . $row;

	return $rowID;

}, 10, 2 );