Can't Edit Old Posts?

Why can't I edit post's I made a long time ago. I wanted to change the title of my grow log, but I can't edit it anymore.. Is there a limit to the amount of times you can edit, or is it just like after X amount of time you can't edit it anymore? Or am I just retarded?

You get like a week or something like that.
Peace

6 days I think........IDK

O well! Theres somthing for the suggestion box. lol

I thought it was only 5 minutes?

I thought way back when you could edit just about anything. I think I could practically go through a whole journal and edit everything I typed. Oh well, pay attention to grammar and punctuation now.