A warm-season vegetable, the green bean (or snap bean) grows best when temperatures range from 70 degrees F to 85 degrees F, according to the University of Connecticut. If temperatures are colder than that, germination can become seriously delayed or will not occur at all. Planting of the tender crop should take place in May or June to ensure protection from a late-season frost. Sow numerous crops at two-week intervals to ensure continued bean production over an extended time period.
Varieties and Planting
Green beans are available in either bush or pole varieties. Bush varieties grow best in rows that are spaced 18 to 30 inches apart. Place individual bush green beans 2 inches apart and then thin after germination occurs so there is at least 4 inches between plants. Pole beans should be placed in rows that are located 4 feet apart. Each seed is spaced 2 inches apart in rows. Pole beans require a trellis or stakes to climb, but bush beans utilize each other for support when growing.
Cultivation and Roots
Apply 2 to 3 inches of mulch around the green bean plants to protect the roots from the hot sun, keep the soil moist and help reduce weeds. The root system of the green bean plant is quite shallow, so deep cultivation will easily damage the plants. Applying mulch will help aid in cultivation and preserve the delicate root system from damage.
During the growth of the green bean plant, keep it moist but not water-logged. Applying 1 inch of water per week is normally ample for the plant. Keep the soil moist to a depth of 6 to 12 inches.
Apply one application of 10-20-10 or 10-10-10 fertilizer at a ratio of 2 to 3 pounds per 100 square feet. Fertilize after germination begins. Water the fertilizer into the soil thoroughly.
The harvest of green beans takes place when the beans are still immature. Constant harvest of immature beans allows the plant to continue production. If the beans are allowed to mature on the vine, the plant will cease producing beans. Once bean production ceases, the plant dies.