Sealing doors

I'm looking for tips and tricks for sealing the entry door into a sealed room grow room. It's just a regular hollow wood door.

If you go down to your local hardware store just tell them you need to seal an external door in your house and ask them the best way to do it. That way they have the product there to sell you rather than us give you a bunch of ideas/ products that you can't get where you are at. Just a thought. You don't have to tell them that the door is on a grow room just tell them it is a door to your garage or some shit!

The easiest way I have found to seal a door is with 4 mil black pastic and Velcro. I run Velcro over the door trim then cut a piece of plastic to the desired size I then put Velcro along the plastic. Keeps light out and keeps co2 in.

I should have added that I want the door to appear unaltered from the "public" side. It is also the only way in or out of the room.