Butter beans, also known as lima beans, grow best in warmer soils and longer growing seasons. Whether you're planting butter beans from seed or nursery plants, wait until soil temperatures reach 65 to 75 degrees F., usually in late April or early May in North Carolina. You can grow either the pole or bush variety of butter beans in your garden, but most people opt for pole butter beans due to their more efficient use of garden space.
Space your bush-type butter bean seeds about 3 to 4 inches apart. Plant your pole butter beans in groups of five seeds around each pole, thinning the seedlings down to the three strongest ones after they germinate.
Plant the smaller bush-type butter bean seeds ¾ to 1 inch deep into the soil. Sow the larger pole butter bean seeds 1½ inches deep in groups of five around each pole, planting the seeds in small mounds around the poles.
Erect a trellis for your pole butter beans by inserting tall wooden stakes or poles into the ground spaced about 12 inches apart and in rows 2 feet apart. Run twine in three or four evenly spaced rows along the poles.
Water your butter beans deeply to soak the soil once a week when rainfall is less than ¾ inch. After blooming, water the butter beans twice a week when rainfall is less than ½ inch.
Feed your butter bean plants 1 pound of granular 5-10-15 NPK (nitrogen-phosphorous-potassium) fertilizer per 100 square feet of ground area around the plants. Spread the granular fertilizer on the soil surface right after planting the butter beans.
Feed your butter beans with a side dressing of 2 pounds of 5-10-15 NPK granular fertilizer for each 100 linear feet after the plants begin to grow upward. Spread the fertilizer along the row about 3 inches away from the plants.
Side dress the butter beans again about four weeks after germination with ½ pound of ammonium nitrate per 100 linear feet. Apply the nitrate on the ground along the row about 3 inches from the plants. Repeat the application two weeks later.