If the cops were trying to bust you for growing pot, there would not have been a patrol car sitting in front of your house for you to see.

Imagine:
Officer Schmeddly: "Hey Bob, you think since we've found these plants at this guy's house, we should go park out in front of the place? Ya know, give him some advance warning of our bust that we've been working for....."

Officer Jablowme: "That sounds like a good idea...."

Being paranoid is good, but some critical thinking can go a long way as well...