(Chicago Manual of Style 14.208)
Author of Entry, "Name of Entry," Title or Description of Blog (blog), date of post, URL.
1. Andrew Cannizzaro, “Presidents’ Day: America’s Need for Three Day Weekends,” Bio Blog, February 14, 2014, http://www.biography.com/blog/presidents-day-video.
Author of Entry. "Name of Entry." Title or Description of Blog (blog). URL.
Cannizzaro, Andrew. “Presidents’ Day: America’s Need for Three Day Weekends.” Bio Blog. February 14, 2014. http://www.biography.com/blog/presidents-day-video.
After title or description or blog, the word blog should appear in parentheses unless it is included in the name like the example above.
"Citations of blog posts, like those of newspaper articles, can often be relegated to the text or notes... if a bibliography entry is needed, it should be listed under the author of the post." (CMS 14.208)