A short distance north is a Poke Mart employee. Speak with him to obtain a free Potion. Further north is a Trainer who will challenge you to a battle before you can leave Route 1 for Viridian City.
Don’t worry, this battle will be easier than your Rival. Defeat Ronny to receive P60 and 3 Poke Balls. Head north to return to Viridian City.