Purple Vetch
Purple Vetch (Vicia benghalensis) is a cool-season annual legume used in California cover crop systems for biological nitrogen fixation, biomass production and soil cover. Its climbing growth habit, tendrils and distinctive purple flowers make it a useful component of diverse winter cover crop mixtures.
Why Plant Purple Vetch?
Purple Vetch adds legume function, climbing growth and flowering diversity to cool-season cover crop systems.
Nitrogen Fixation
When effectively inoculated and nodulated, Purple Vetch can biologically fix atmospheric nitrogen and contribute nitrogen-rich residue to the cropping system.
Biomass Production
UC ANR reports approximately 3,000–7,000 pounds of above-ground biomass per acre under documented California cover crop conditions.
Soil Cover
Vining growth can help occupy open space and provide vegetative cover during the winter growing period.
Weed Competition
A productive stand can contribute canopy cover that competes with weeds when establishment is successful.
Pollinator Flowers
Purple flowers can provide floral resources for bees and other pollinating insects when the crop is allowed to reach bloom.
Mix Diversity
Purple Vetch can be combined with compatible cereals, peas, bell beans and other legumes in multi-species winter cover crop mixtures.
Planting Purple Vetch
UC ANR lists approximately 15 lb per acre as a straight-stand seeding rate for Purple Vetch.
Plant approximately ½ to 1½ inches deep, depending on soil texture, moisture and planting equipment.
Purple Vetch is typically planted in mid-fall for winter and spring cover crop production. In mixtures, reduce the component rate according to the desired proportion of the finished stand.
Moisture Note: Purple Vetch has relatively poor drought tolerance compared with some other vetch species. Adequate seasonal rainfall or supplemental moisture improves establishment and biomass potential.
Best Uses for Purple Vetch
Winter Cover Crops
A cool-season legume option where nitrogen fixation, biomass and living soil cover are desired.
Orchards & Vineyards
Can be incorporated into compatible winter cover crop mixtures between permanent crop rows.
Multi-Species Mixes
Combines particularly well with upright cereal or broadleaf species that add structural diversity to the stand.
Pollinator Cover
When allowed to flower, Purple Vetch provides distinctive purple blooms attractive to pollinating insects.
Manage Growth Before Mature Seed Set
Purple Vetch is relatively late maturing, so termination timing should balance biomass and nitrogen goals with the requirements of the following crop.
Support Nodulation
Use an appropriate vetch inoculant when needed to support effective nodulation and biological nitrogen fixation.
Maintain Establishment
Adequate moisture is particularly important because Purple Vetch has lower drought tolerance than some alternative vetch species.
Terminate at Full Bloom
UC ANR lists close mowing at full bloom, tillage and herbicide as possible termination approaches depending on the production system.
Prevent Unwanted Seed
Purple Vetch may become weedy if allowed to mature and produce viable seed. Terminate before seed set where volunteers are undesirable.
Perennial Crop Note: In orchards and vineyards, monitor cover crop biomass and soil moisture so vigorous spring growth does not create unwanted competition with the permanent crop.
Looking for Purple Vetch Seed?
Contact Weaver Seed for current Purple Vetch availability, quantities, pricing or help incorporating it into an orchard, vineyard or field cover crop program.
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