Hey, bamaranch. Ken here with The Home Depot in the Chicago area.
I can relate to trying to save on your water bill. But if your preemergent is
mixed with fertilizer, there is a chance of it burning your lawn if itís not
watered in right away. If you are putting down straight preemergent, then
you should be fine.
One thing to consider is that the sun will start to break down the granules
over time and reduce their effectiveness. It all depends on the weather on
those 4-5 days. Good luck.