Green Manures — You Can Use Them to Improve Your Soils

Why use green manures?

Green manures boost soil fertility, improve soil structure and support the biodiversity of life in the soil. They typically have high nutrient content and when put back into the soil, also contribute to soil organic matter. Soil organic matter is critical for good plant growth. They improve soil structure even when growing as their roots help break up compacted soil and allow for water and air to penetrate the soil. Some even help to suppress weeds and reduce pest populations.

What are green manures?

Green manures are crops that you grow specifically to be put back into the soil while they are still green . Examples are lablab, pigeon pea and cowpea. At the point of flowering, you will turn it back into the soil by mowing or chopping it and mixing it in with a fork a plough or a disk.

How to use green manures

Choose the right green manure crop: The type of crop depends on your soil type, climate and the nutrients that the crop you will plant afterwards needs. For example, legume crops fix nitrogen from the atmosphere in the soil, which can then supply nutrients to the plant.

Prepare the soil and sow seeds: Prepare the soil by clearing the bed and either broadcasting the seed or placing into planting holes.

Incorporating into the soil: Let the plant grow until just before flowering and then either mow or chop the crop and turn it into the soil by hand or with a plough. Disturb the soil as little as possible.

Allow time for decomposition: Allow some time for the green manure to decompose and release its nutrients into the soil. This can take several weeks, avoid planting other crops during this time to allow for decomposition.