In a large pot, cover the beans with cold water by at least 2 inches. Add herb sprigs, the whole onion half, and garlic cloves and bring to a boil over high heat. Reduce heat to simmer and cook until beans are very tender, about 1 to 2 hours. Season with salt. Drain beans, reserving bean-cooking liquid. You should have about 3 cups of cooked beans; if you have more, measure out 3 cups of beans and reserve the rest for another use. Discard herb sprigs, onion, and garlic.
