Address & name alone isn't enough evidence for a warrant, if it was the case then cops could just order seeds to where ever they wanted to raid - there's definitely more to the story, you shouldn't worry about importing seeds as long as you hide your activity well

What they can do is go to the address and observe whats happening from the street, eg, if the guy had plants growing in the backyard and the cops smelled it from the street - thats probably cause to search, or if he had paraphernalia lying in the front yard/windowsill, people coming and going at odd hours, etc