Controlling non rgb led strips with arduino uno

So I bought an arduino uno with the intention of using it to turn on and off non rgb light strips. It's being used for a simple halloween decoration. I have 12 seperate strands of light strips. I have the hot running to a 12 volt battery, each strand has a negative running to the source side of the mosfet. The gate side is running to the uno. The ground from the uno it running to the 12 bolt battery as well as the drain for each mosfet. And the uno is powered by a 9 volt battery. All the led strip are illuminated when powered is applied instead of being off. You can vaguely see the chase effect so I know the code works. I need the leds to not be constantly on. What am I missing? (I am new to this as well)

Will do. It's all hooked up to a bread board at the moment so it's kind of a mess. The mosfet I used "WeiMeet RFP30N06LE 30A 60V N-Channel "