unless you're dealing with autos, when a plant "finishes" is dependent on it's light cycle. plants finish differently in different geographical locales. plants adapt to the change in the season and the shorter sun periods by going into flower. you can determine when it'll flower by altering the cycle. certain strains have longer or shorter flowering periods and/or cycles but it's still a matter of periods of light.
it's still easier to manipulate the cycles indoors.
plant early and pick a fast finisher.