Bean Plant Nutrition

Types

• Horticulturists recognize 17 chemical elements essential to normal plant growth, and the bean plant is no exception. Those needed in large amounts are called macronutrients. Plants can obtain three of these--carbon, hydrogen and oxygen--from the air and water in the environment. The six additional essential macronutrients are calcium, magnesium, nitrogen, phosphorus, potassium and sulfur. Micronutrients, elements required in much smaller quantities for normal plant growth, are boron, chloride, cobalt, copper, iron, manganese, molybdenum and zinc.

Features

• Leguminous plants, which include beans, are distinct in that they are able to also obtain nitrogen from the atmosphere by housing nitrogen-fixing bacteria in special root nodules that convert the element into a form the plant can use. However, an excess of this element causes bean plants to put more energy into leaf growth and less into pod and seed development. Therefore, care should be taken in applying extra nitrates to the planting area.

Effects

• After the plants have established root systems, beans require adequate watering, either from rainfall or the gardener's assistance. The water acts as a solvent, providing the root system with a liquid nutrient mix for uptake. This is essential from the time the first flower buds form until seed formation to prevent blossom drop. Conversely, excess watering can create multiple problems. Bean plants need about 1 inch of water per week for ideal absorption of nutrients.

Considerations

• Obtaining a proper balance in the soil can also help to achieve optimal nutrient uptake in bean plants. This balance can be achieved by testing a soil sample and providing additives if necessary to reach the optimal pH. According to experts at North Carolina State University, snap beans prefer a pH of 5.5 to 6.0. Side-dressing lightly with a chemical fertilizer mixture or lime may restore balance, depending on the soil test results.

Significance

• If chemical fertilizers are used, apply a mix lower in nitrogen than potassium and phosphate. For example, a 5-10-10 fertilizer has twice the amount of phosphate and potash than that of nitrogen. Adding organic matter (compost and manure) to the planting area can provide the nutrients needed without the addition of chemical fertilizer products. In the right soil, bean plants are easy to grow and require minimal attention in relation to the amount of crop yields produced.