Add "Read more" in excertps of blog posts in home page

I’m assuming your homepage contains Posts, not Pages.

Step 1: From WP Dashboard go to Settings>Reading
For each article in a feed, show = SUMMARY

This will give you a […] link to the full post after 55 characters.

Step 2: If you want to change this to ‘Read More’:
http://wordpress.org/support/topic/how-to-change-the-more-text-after-the-excerpt

Assuming it is resolved, can you set this as Resolved please. (Dropdown in right sidebar) Helps monitoring what problems are still outstanding.