I give my students two weeks to fill in their journals for a week. I don't think it is usefull for them to write about something that happened more then two week ago.

After two weeks I give them feedback which they can use for the next week.

As a student they cannot modify that period through the main page of the course.

However when they click on journals in the activity block on the left they still have the option of editing their (very) old journals.

I don't think that it meant to do that, but maybe I am wrong