Green Manures – What is It and What Does It Do for My Garden Soil?
Green Manure: Green manures are basically cover crops that are grown with the intention of turning them back into the soil. Obviously this would be more useful in the vegetable garden or in a newly created bed where tilling will not harm existing perennial plants.
Different green manures offer different advantages. Some, like alfalfa, are grown for their deep roots and are used to breakup and loosen compacted soil. The legumes, clover and vetch, have the ability to grab nitrogen from the air and eventually release it into the soil through their roots.
If allowed to flower, clover especially is attractive to pollinators and beneficial insects. All green manures will suppress weeds and prevent erosion and nutrient runoff in areas that would otherwise be unplanted. And they all assist with creating good soil structure and food for the microbes, once they are tilled in and begin to decompose.
Popular choices for green manure include:
- annual ryegrass
- winter wheat
- winter rye.
Green manure, unlike traditional manure, is not made from animal waste. Both types of manure are decommposing waste, but green manure probably has more in common with compost than with animal manure. It certainly smells better than animal manure.