Done in days prior to the event. Not sure what you have there- real brown dirt, red clay, western desert, ??- but keeping things watered on a regular basis will help. Then you can stop a day or two before the event to let most if not all of it dry out on top.
The watering should help keep whatever small amount of grass you have and help it spread. Encouraging that would be good. The root structure and longer grass tops will help keep dust down, especially if watered.
My studio has a clay floor and the dust is most effectively managed by watering to keep it from becoming airborne. If I water at the end of the day, it's nice and dry the next day as long as I don't over-water. When it's really hot, I watering the morning (and again as needed) to help cool things down some. The more often I water the floor, the better.
1967 Galaxie 500 Red original Q code 428
1967 Galaxie 500 White with Black stripes 428PI clone- car is dead & long gone, sold near Oak Ridge TN 2000, would love to find it.....
Please visit http://carolinasculpturestudio.com/
for pictures, information and video links to my work.