Combine the greens and garlic in the bowl of a food processor fit with the chopping blade. (The smaller the food processor the better here, as the greens might escape the blade in a large machine.) Pulse until the the greens are finely chopped.
Add the lemon juice, olive oil, and 1/2 teaspoon of salt. Process until you have a thick pesto, stopping to scrape down the sides of the bowl with a silicon spatula if you need to. Taste, and add more salt if needed.