Lacking Motivation

My freshmen students seem to be lacking motivation when it comes to their weekly writing task. Each Monday, I give the students an optional journal prompt. They are supposed to write me 1-full page by the end of the week. I give them 15 minutes of class time to do this. If they don't like the prompt I give them, they are allowed to write about their weekend or anything else that they would like. It's a great way to get the students writing, and it also gives me a chance to get to know them a little bit better. And to top it off, it's an easy 10 points for them. However, for some reason, each week without fail, I have a handful of students simply not complete their journals. It's so frustrating!

I'm looking for ways to get them motivated to enjoy this writing task more. I read every journal and write comments back to try and engage them. It works for some of them. I've had comments like, "I love when you write back to me!" and "I like reading your comments!". However, it doesn't seem to work for all of them.

One thing that I know I need to change is that I need to write WITH my students. That was a big thing that was stressed in my undergrad classes. It's so important to write with your students because they need to see you doing it, too. Maybe me writing and sharing my writing with the students will be motivation for them to do the same. I'm going to give it a shot. Any other ideas out there?