Bush beans take 50 to 55 days to mature for harvesting, and pole beans take 50 to 60 days to mature, depending on the variety, according to About.com. Pole beans often take slightly longer to mature because the tall vines need a little more time to grow.
Once bean plants are mature, the beans can be picked every day or two, according to Burpee, a seed distributor. Frequent harvesting causes the plants to produce more beans. Beans are ready to be picked when they are firm enough to snap and their thickness is about the diameter of a pencil, according to About.com.