Plant Vetch as an Ideal Cover Crop
In addition to fixing nitrogen, a vetch cover crop improves soil health and structure. Hairy vetch and common vetch are widely used as cool-season cover crops. They are annuals that can easily be killed when time comes to plant the main crop. Crown vetch is an extremely aggressive perennial that is used for erosion control, not as a cover crop.
The root systems of cover crops like vetch condition soils by maintaining pore spaces that allow for air and water movement. This helps improve the tilth or loose, crumbly structure of the soil. In comparison, bare soils often become compacted, pore spaces are compressed, and movement reduced.
Vetch grows very quickly and produces a vast amount of plant tissue that contribute to the organic matter or biomass of soils. When vetch dies, the tissues breakdown quickly and thoroughly, releasing nutrients into the soil. In addition to nitrogen, vetch provides more phosphorous than many other cover crops.
Mature vetch can be used in a number of ways to improve soils. Vetch is typically killed in the early flowering stage to prevent plants from going to seed. Plants are easily killed by cutting stems at ground level. It is best to cut vetch two to three weeks before planting a crop.
Cut tissue can be incorporated into the soil as a green manure or left on the soil surface to serve as a mulch. Incorporation adds organic matter and improves soil structure, promoting good drainage and increasing a soil’s ability to retain water and nutrients. Using vetch residue as a mulch helps to retain soil moisture otherwise lost to evaporation and provides weed suppression.
Plant Vetch to Reduce Stormwater Runoff and Soil Erosion
Cover crops provide another important benefit to the landscape: they reduce soil erosion. Exposed soils are easily washed away by wind and rain, robbing the garden of a rich growing medium. Eroded soil is typically deposited in streams, rivers, and lakes where it reduces water quality and habitat. Pesticides and fertilizers carried with the soil are a significant source of water pollution.
Plant vetch to stabilize soil and reduce erosion. In gardens and fields, hairy and common vetch make ideal cover crops during the fallow season. Plant roots and vegetation protect soils from wind and water. Crown vetch provides excellent erosion control on steep slopes and other areas where plants are difficult to establish.
Cover crops reduce stormwater runoff by maintaining a porous soil where water can infiltrate freely. Rather than sheeting across the soil surface, rainwater penetrates the soil and moves down into the water table. Increased infiltration also prevents water from standing or pooling on the soil surface which leads to the formation of a hard soil crust.
Plant Vetch to Combat Weeds
Hairy and common vetch grow rapidly in the spring, outcompeting early-season weeds for sun and water. Such competition provides a low-maintenance form of weed management for the spring garden.
Vetch residues left on the soil surface after cutting continue to suppress weed growth by shading soils and smothering new growth. This benefit lasts about three to four weeks as the crop establishes and vetch decomposes, releasing nitrogen into the soil. Vetch is commonly used in this way as a mulch for tomatoes.
Vetch can also be used as a living mulch alongside cool-season crops like broccoli and cabbage. Actively growing alongside the crop, vetch provides nitrogen and battles weeds. Vetch is also planted in orchards such as pecan groves to attract beneficial insects. Lady beetles, big-eyed bugs (Geocaris spp.), and pirate bugs (Orius spp.) are prominent among vetch. When left to flower, vetch also attracts an abundance of honeybees and native bee species.