There is research ongoing on the benefits of a hairy vetch cover crop fror
tomatoes. Traditionally hairy vetch has been used in combination with rye as a
winter cover crop (green manure). One study just summarized in The American
Vegetable Grower is by Abdul- Baki a t the USDA Sustainable Agricultural
Systems Laboratory at Beltsville Maryland. Note that the comparisons are with
plastic mulch and on irrigated crops and for areas without crop rotation. There
is no question that green manures work and that sod planting is viable. Whether
hairy vetch is superior to other legumes like clover or even other winter cover
crops is still open to debate.