Beans and Peas - including such flowering plants as the Sweet Peas, and all members of the Legume family of plants. This family also includes trees, perennials and shrubs and are all important in one particular respect.
They are all able to 'fix' the all important plant food Nitrogen from the atmosphere. This is stored in small but visible 'nodules ' on the root system, and is often left in the soil after the plant's death.
The Nitrogen is obtained from the atmosphere by a symbiotic relationship with the nodules and certain bacteria.
Legumes are important for many agricultural purposes - especially on soil that has become depleted of Nitrogen. In the garden, this phenomena is useful for the production of leaf crops nearby, that need plentiful supplies of Nitrogen - (see NPK). Together with this, if the old stems and foliage of Legumes are dug into the soil, there will be less need for added nitrogen fertiliser.
An all important - but often overlooked - advantage of using your Legumes for Nitrogen, is the fact that it is a wholly organic source of one of the most important feeding elements for plants - Nitrogen! Organic vegetable growers rarely realise the full potential of growing Leguminous plants for this food source.
Peas and beans as vegetables, have a high protein content, which is probably as a result of the added Nitrogen available to the plant from the action of the root nodules. Plants generally are a good source of protein - whatever the dieticians say. Legumes in particular are high in this essential food source for humans. It does not have to be meat!
The Nitrogen element of plant food is essential in the overall growth of the plant, and for foliage in particular. That is why it is often recommended to grow leafy salad crops such as lettuce, near to, or directly after a Legume crop.
Below are a few links to members of the nitrogen fixing legume family. They are all everyday vegetables that we love so much.
Broad Beans - Sowing in winter or spring?
Sowing and growing French Dwarf Beans. Pots or garden.
Runner beans - Sowing and Growing
How to Grow Peas - Shell Peas; Sugar Snap Peas; Mangetout Peas: