functions.php

<?php

add_action( 'genesis_entry_content', 'kat_grid_content', 9 );
/**
 * Change the number of words in excerpt if in the grid loop and customize READ MORE, add accessibility.
 */
function kat_grid_content() {
	// Make sure we're in the grid loop.
	if ( ! apply_filters( 'is_genesis_grid_loop', false ) ) {
		return;
	}

	// Change length of teaser.
	$length = 55;
	if ( in_array( 'teaser', get_post_class() ) ) {
		$length = 25;
	}

	echo '<p>' . wp_trim_words( get_the_excerpt(), $length ) . '</p>';

	// Display more link.
	printf(
		'<p class="more-link"><a href="%1$s">%2$s<span class="screen-reader-text"> %3$s %4$s</span></a></p>',
		esc_url( get_permalink() ),
		esc_html__( 'Read more', 'your-text-domain' ),
		esc_html_x( 'about', 'i.e. Read more about A Post Title', 'your-text-domain' ),
		esc_html( get_the_title() )
	);

	// Remove default content so we don't get both.
	remove_action( 'genesis_entry_content', 'genesis_do_post_content' );
}