Use this syntax in Google: YOUR KEYWORD+inurl:blog site:.edu This will give you .edu blogs to comment.
Use the following search query: site:.edu inurl:blog "niche/keyword". For even better and more targeted results, check the post I wrote ( link in sig)
www.stanford.edu www.harvard.edu www.usc.edu www.tamu.edu www.umd.edu www.pitt.edu Here are just few .edu sites for your blog