Way back when I was a newbie I also wanted to remove a thread that I had started. Mostly I was getting tired of receiving the notifications. The information in your thread...well, if you hadn't edited it out...could be useful to future newbies. Maybe you can "unwatch" the thread?
Edited to add:
Not too long ago I started a thread to ask a specific question about Bumblebee behavior. After I was satisfied with the answer folks kept using the thread to talk about other things - lots of other things. I wanted to close that thread and ...well...it got pretty ugly for a while. The thread started here:
http://garden.org/thread/view_...
Hopefully everyone will be nicer to you than they were to me.
