This one is highly biased to what you prefer to put in your smoothies. I’m going to list some common smoothie & juicing foods, but obviously, if you find that you buy something regularly for your smoothies that you can grow. Then add it to your planting list!
Strawberries: There are 2 types of strawberries you should plant. June-bearing strawberries which produce one large crop in June! Hence the name. So you can eat your fill then freeze the surplus to use in smoothies.
Kale: kale is close relative to the Brussels sprouts, broccoli, cabbage. The nutrient-packed leaves are easy to drop into a mixer to add a little vitamin to any smoothie you make. You should plant kale seeds in early spring. When the plants grow clip leaves often to encourage new growth.
Blueberries: They grow best in full sun, sandy, well-drained, acidic soil. There are 2 kinds of blueberries: highbush, that can grow over six feet, and lowbush, that grows about one foot tall.
Cherries: To grow your own cherries for smoothies, you need an area that receives a minimum of six hours of direct sun daily. Sweet cherries need a lot of air flow around them, to keeps them free of a disease called brown rot.
Cucumber: a single cucumber plant can produce a lot of cucumbers -- for salads and smoothies. Cucumbers are available in 2 types: Picklers which are short and jolting. And slicers which are long and skinny. Plant cucumber in a sunny spot.
Honeydew Melon: honeydew melons have light green or orange flesh. Melons are simple to plant and grow, but need a large area to spread. They love sun light. Plant in early spring once the frost danger has passed.
Apples: although it takes 3 to 5 years for a newly planted tree to produce apples, it’s worth the time and work. Apple trees come in full-size, semi-dwarf and dwarf heights. Small varieties like the dwarf type may be grown in containers.
Mint: Mint is one of the easiest-to-grow herb. In fact it's so adaptable it can be invasive. The Best way to plant your mint is in a big container. This herb produces lots of flavorful leaves, good for making a smoothie.
Spinach: is an easy to grow edible plant leaves can be raised in garden beds or containers. This cool-weather crop may be planted in early spring and harvested for weeks. You can harvest the plants and use them in your smoothies, then replant again in cooler weather.
Raspberries: They come in red, black, purple, and yellow. There are 2 varieties of Raspberries: “summer bearing raspberries” and “fall bearing raspberries”. They grow on long and thorny canes, and reach up to six feet tall. Raspberries are perennials and can regrow year after year. Plant in a sunny spot.
Peaches: Peach trees bear fruit 2 to 3 years after planting. They flower in the spring, then the flowers turn into fruit that grows large throughout the summer. Pick varieties that best fit your zone; some varieties, like ‘Reliance’ are especially cold hardy.
For more info get this book "The Green Smoothie Garden" it have a lot of nutritious green smoothie recipes.
See also: How To Make a Raised Bed Salsa Garden
And: Here's how to grow a pizza garden