- You will get 500 Seeds of Hairy Vetch Bulk Nitrogen Fixer Cover Crop Companion Plant To Tomato Vegetable Seeds. - Sunlight: Full Sun, Medium Sun. - Soil Type: Clay, Loam, Sand, Silt. - A legume that is widely used as a cover crop, a great companion plant for tomatoes. - Rotating crops, fall/winter vetch to spring tomato is commonly done. - Hairy Vetch provides both nitrogen and mulch and can keep weeds from sprouting.