Answer for I have a 25 gallion ATV sprayer. What ratio of Plot Start to water for a one acre plot.

Mix the 2.5 gallon jug of PlotStart that treats 1 acre into however much water it takes to evenly spread it across the acre plot. If it only takes 10 gallons of water to spray the 1 acre plot than mix all of the 2.5 gallons into the tank with the 10 gallons. There is a video on the home page  showing how to determine this.