Spinach is commonly used to make this green smoothie. So if you make this green smoothie as a beginner you can use this spinach or kale. That is why when you buy spinach in the market, you can buy in a large quantity and keep it frozen in the refrigerator. There are also many other vegetables that can be used in this green smoothie, to name a few:
Beet Greens
Carrot Tops
Collard Greens
Celery
Spinach
Kale
Swiss Chard
Romaine Lettuce