I knew I had a passion for plants when...
There are other things I run to at other times.
There is God, there is sugar and there is the sweet sweaty arms of babies or the strong, rough arms of my husband.
I knew those were passions - I've known that for a long time. Sometimes though you think things are just hobbies. Just things you like to do. Sometimes they are just ways to make money -- a job. Sometimes though, when you run to those things, you might have just found a passion.
...now the question is -- how many passions can a person reasonably have? Hmmm-hmmmm?