I have done tons of air drying over the years:
If the boards have sawdust on them, wash it off with a garden hose
before stickering. That sawdust holds moisture and dirt dust that can
mold and mildew, causing black discoloration on the lumber.
If you are in a low humidity area, you may want to wet the boards
daily so that they don't dry too fast, however you don't want the
boards to rot. Do this as best you can so that the wetted boards
drain well.
Don't sticker the lumber in direct sunlight...some boards will dry too
fast. For air drying lumber, a slow-drying process is best. Fast
drying lumber will check and warp.

Check around for a kiln and see if the price for kiln drying is in
your budget.

Sonny