As long as you keep children out of the area while you treat and until the Scotts Lawn Pro Weed and Feed Weed Control Plus Lawn Fertilizer treated area has had time to completely dry or settle it is safe for pets and people to return and resume normal activity. Typically 4-5 hours is best.
No Scotts Lawn Pro Weed and Feed Weed Control Plus Lawn Fertilizer label specifies not to be used on St. Augustine grass.
You would need to refer to the product label for the settings if yours is listed. You can also try calling Scotts directly, to see if anyone on their staff has that info. Otherwise, if your type is not listed on the Scotts Lawn Pro Weed and Feed Weed Control Plus Lawn Fertilizer label you will need to calibrate your spreader to the rate for your turfgrass.
You can see a short video on how to accomplish this here.
