Green beans grow in pole and bush varieties, and may be one of a large number of cultivars. Green beans used for cooked dishes and salads as crisp, green pods are always early-harvest beans. Like all vegetables, bean plants need the right mix of season, sun and care to survive and produce their vegetable harvest. Brown, dying leaves occur when they don't get the right conditions for healthy growth.
Bean plants are summertime growers, and require specific planting dates and growing seasons. Set beans out in the garden in spring, after all chance of frost passes, and maintain them through summer to fall. The plants die when they get late spring frosts, and die back in fall when temperatures fall under 60 F.
Bean plants require full sun all day, and yellow and die in shade. Keep the plants in areas that get full sunshine, and give them the right spacing to maintain air circulation and sun exposure. Plant bush beans at 2 to 4 inches in the row, in rows spaced at 18 to 24 inches. Space pole (vining) beans at 4 to 6 inches in the row, in rows at 30 to 36 inches. Pole beans need a trellis for support during their growth.
Soil and Nutrition
Beans grow poorly in soil that is tight, too wet, too dry or poor. Lack of soil quality leads to leaf death and eventually plant failure. Mix 3 inches of organic compost into the top 3 inches of soil around each bean plant to give the plant more nutrition, quicker drainage and better access to moisture for leaf recovery. Purdue University suggests supplementing even rich soil with an application of 33-0-0 fertilizer once pod set begins, at a rate of 1 cup of fertilizer per 50 square feet of planting, to give the beans better nutrition for growth.
Adequate moisture is important throughout a bean plant's life, but is especially important during blooming and fruit set. Bean plants that get enough water produce continuing harvests, while those that don't get enough water experience leaf die back and failed blooms. Always water green beans with at least 2 inches of water a week, with the right soil, to maintain the necessary moisture level.