How close can I put a raised garden bed to a crawl space sweep?

I'm wanting to put a raised garden bed close to the exterior of my slab in my backyard . The garden bed is 17 inches tall and does come to the top of the sweep. Right now I have it a foot away but would like to get it closer if possible. The sweep is right in the middle of where the bed needs to go so I want to know how close I can put the garden bed to the sweep without interfering with the sweep ventilation.