Fava beans are protein-rich crops commonly grown for fresh consumption and for use in different dishes. In addition to their culinary value, many gardeners grow them to support and improve soil health. In this article, you will learn about the most important benefits of growing fava beans for the soil.
Nitrogen Fixation
Nitrogen fixation refers to the process in which nitrogen is converted into a form that is available and beneficial for plants. All plants absorb nitrogen, but legumes—such as fava beans—have a high ability to absorb nitrogen from the air and fix it in the soil.
This happens through special bacteria that colonize the roots of legumes and form small nodules that extract large amounts of nitrogen.
The nitrogen absorbed by these bacteria is usually more than the plant needs; therefore, the plant stores the excess. When the plant dies, the stored nitrogen is released into the soil in large quantities, helping other plants grow, as nitrogen is essential for producing amino acids, nucleic acids, proteins, and other growth-supporting compounds.
Farmers often rely on synthetic nitrogen fertilizers to supply crops with nitrogen, but growing fava beans and other legumes provides nitrogen naturally without harming plants or the environment with industrial pollutants.
Some farmers grow fava beans as a winter cover crop to enrich the soil and prepare it for spring planting, while others include it in crop rotation or plant it alongside crops such as Brassica, lettuce, and potatoes to help with germination.
Attracting Pollinators
Fava beans are self-pollinating and do not require bees or insects for pollination.
However, studies show that bees and other pollinating insects are attracted to fava bean flowers for nectar. Planting fava beans in the fall helps provide nectar early in the year—especially in gardens with limited floral resources for pollinators.
Providing Green Manure
Green manure refers to plant material used as organic fertilizer that enriches the soil, suppresses weeds, and prevents erosion. It protects the soil and prepares it for future planting.
To grow fava beans as green manure, follow these steps:
- Scatter the seeds in the soil after summer crops have been harvested and the garden beds are empty. Spacing is not important since the goal is to produce green manure rather than beans.
- Allow the seeds to germinate while keeping the bed free of weeds until seedlings appear.
- Leave the plants throughout winter. When you want to plant new seedlings or seeds, cut the fava bean plants at soil level and leave them for 1–2 days to wilt. This should be done six weeks before planting new crops.
- Dig a hole at least 25–30 cm deep and plant your new seedlings. The remaining fava bean roots will decompose in place and give the new plants a strong, nutrient-rich start.
