Does Sand Affect the Way a Bean Can Grow?

Sandy Soil

• Some amount of sand in the soil is good for many beans, because it ensures a porous growing medium so water can drain efficiently. This prevents the occurrence of rot and fungal diseases, which beans are prone to. But many dry beans do not thrive or produce well in sandy soil. Too much sand can make the soil drain too quickly, and dry beans lack strong root systems to obtain sufficient moisture in soils of that type. Sandy soils also tend to be high in salts, which dry beans do not like. But the blackeye bean, a type of cowbean, actually thrives in sandy soil due to its vigorous root system.

Loam Soil

• While dry, sandy soil is not preferable for bean growth, neither is the other extreme of compacted, poorly drained soil. Somewhere in between, a soil that's loamy with some sand and plenty of compost or organic material is ideal. Simply adding compost or manure, whether your soil is clay or sand-based, will improve its texture and water-holding capacity. As a general rule, beans thrive better in rich, well-draining soil rather than sandy soil. That said, bean plants can still thrive in plain sand, unless it's is water logged. A soggy growing medium will lead to fungal diseases in bean plants.

Aerated Soil

• Loose soil is generally ideal for many bean plants, as it allows them to stretch their roots and drain well. Adding sand may be necessary to achieve this loose texture. You can identify poorly draining soil when water collects and pools at the surface and does not drain quickly, leaving it wet for long periods. Stunted plants and the appearance of necrotic spots on leaves and stems are signs of fungal disorders associated with poorly draining soil. Incorporate sand to avoid these problems. When adding sand to clay soil, add at least 4 inches of coarse sand to the top 6 inches of soil you're working with.

Other Soil Considerations

• The texture of your growing medium is just one consideration. Beans are also affected by the pH and salinity of the soil, for example. The ideal pH range is 6.0 to 6.5. Adjust this level with sulfur or lime. Rotate bean crops in new areas of your garden to avoid diseases that may be present in the soil. Provide even moisture to keep roots from drying out or succumbing to rot.