Do you deploy your app every time you write a blog post? I'm on Jekyll also. I wonder if you could hook the `_posts` folder to some sort of CMS and update the content without deploying.
As well as a CMS you'd also need to run jekyll to build the posts into html. You could use github to do all this actually: their web interface can work as a basic CMS that lets you edit and commit individual files, and if you host on github pages they'll build the posts with jekyll after each commit.