Start by filling a jar with fresh water until it's about a quarter full, which is roughly an inch deep.
Take the green onions and place them in the jar with the root side down, ensuring the roots are submerged in the water.
Cover the green onions with a bag, and secure the top of the bag around the jar using a rubber band.
Store the jar in the fridge, where the green onions can stay fresh for 2 to 3 weeks, or even longer.
Remember to change the water as needed, and don't worry if some moisture accumulates inside the bag; that's perfectly normal.
