in medium saucepan on medium heat, bring sugar, salt, butter and corn syrup to a boil while stirring consistently. Cook and stir for another 4 minutes.
Stir in baking soda, and green food colouring. Expect the mixture to foam up and double in size.
Remove from heat.
Place popcorn in large bowl. Pour mixture over popcorn in bowl and toss to coat evenly.