An heirloom variety of pole bean, the Kentucky Wonder green bean (Phaseolus vulgarism, 'Kentucky Wonder') produces large amounts of 9-inch-long pods on its vines. This long-time favorite of gardeners grows in U.S. Department of Agriculture Hardiness Zones 3 through 10. A tender annual, Kentucky Wonder beans should be planted after the last chance of frost has passed in the late spring or early summer.
Because pole beans must be grown vertically on a trellis, prepare a bean support before planting. Bamboo tepees, wood stakes or decorative trellises can be used to support pole beans. Cattle panels make sturdy, inexpensive trellises. Make an arch by securing each end to the ground with t-posts or rebar.
Select an area in full sun that gets at least six to eight hours of sunlight per day. Pole beans thrive in well-drained, loamy soil with a slightly acidic pH of 6.0 to 6.8. When soil temperatures reach 70 to 80 degrees, prepare soil by adding 1/2 inch of compost to the surface and loosening the soil with a shovel or tiller. Remove all grass and weeds.
Plant beans 4 inches from the base of the trellis 1 inch deep and 2 inches apart and water well. Because compost has been added to the soil prior to planting, fertilization is not necessary when planting.
When seedlings reach about 6 inches tall, they begin to vine. When vines are long enough, loosely tie them to the trellis with jute string. Leave about 1/2 inch of space between the tie and the vine so it can move around but not fall. Do not tie the string tightly; doing so can damage the vine.
- Beans rarely survive transplanting, so direct sow seeds outside for the best results.
- Plant pole beans every two weeks throughout summer for a continual harvest.
Water Kentucky Wonder pole beans any time the soil is dry 1 inch below the soil surface. Infrequent, deep watering is preferred over frequent light watering -- less water is lost to evaporation so more water gets to the plant roots. Mulching well around plants with wood chips or straw keeps soil most and reduces the need to water.
Fertilize plants once a month, beginning four weeks after planting, with one tablespoon per square foot of low-nitrogen fertilizer, such as 5-10-10 or 5-10-5. Too much nitrogen leads to large, bushy plants that produce very few beans.
Once bean pods have started growing, harvest them when they reach about 4 inches long but before the beans inside start to swell. The bean pods should be smooth; if you can see the shape of the beans inside they are too mature to eat.
Harvest pods daily. Leaving beans on the vine too long will signal to the plant that it has produced seeds and can stop blooming and producing pods. To harvest, hold the vine with one hand and gently pull off the pod with the other.
Never pull or tug on beans; vines are delicate and will break easily.