Stringless pole beans (Phaseolus vulgaris limensis) are a species of green bean known for its tender, stringless pods. The "string" is a tough fiber that runs the length of the pod of some varieties. These beans are popular for eating right off the vine and have a mildly sweet taste that many find appealing. In fact, green beans are the second most popularly grown vegetable in home gardens, according to Washington State University. Tomatoes are the most popular.
Pole beans in general can grow upwards of 6 feet tall, and stringless pole beans are no exception. The pods of these beans grow to a length of about 5 inches, according to Denver Plants. "Kentucky Blue" is a cultivar of this plant that has pods (beans) that can reach 7 inches in length.
Stringless pole beans, like all beans, should be planted when there is no longer any danger of frost. The seeds should be pressed about 1 or 2 inches into rich, fertile soil and spaced between 2 and 4 inches apart. Most importantly, the seeds need to encircle a support structure--usually a 6-foot-tall wooden or bamboo pole. The pole is used to help provide a vertical space for these climbing plants to grow. String should be stretched between the poles in a zigzag pattern for the bean plants to grow on.
Stringless pole beans thrive in full sunlight and rich, fertile soil. They do not compete well with weeds, especially as young plants. Insect pests and fungal diseases can sometimes affect bean plants, but most, such as the Mexican bean beetle, are not a serious threat to the health of the plant.
Stringless pole beans should be harvested around 65 days after planting, according to the University of Illinois. The pods should not be bulging. If the pods are wet from dew, the home gardener should wait until they are completely dry before picking them, as fungi and bacteria can spread on water. Green beans are harvested and consumed when the developing seeds are still immature.
Beans are a low-calorie, high-nutrient food. One cup of green beans equals only about 31 calories, according to the University of Maine. The same cup provides almost 25 percent of a woman's daily requirement of vitamins A and C. Other nutrients in green beans include folate, which is vital for the growth of developing babies.