As a research intern at the Rodale Institute in , I was lucky to be part of a dormant seeding trial using, creatively, the winter annual cover crop hairy vetch. Dave Wilson, my supervisor at the time and encyclopedia for all things agronomic, got the idea for dormant seeding from hearing stories of farmers in North Dakota who used the practice to get a head start on planting spring wheat, since conditions for driving a tractor in a northern spring can be quite tricky, often excessively wet and muddy. Successful dormant seeding requires that farmers get seeds in the ground before the ground freezes and winter-long snow cover arrives, but not so early that warm weather coaxes a tender sprout from the ground to face the violent elements of winter before it has a chance to put on adequate growth and energy reserves for survival. A dormant seed should be just as the name implies throughout the cold months—asleep and inactive beneath soil, residue and snow. Fall temperatures during the experiment year were warmer than usual, so many time-strapped farmers were calling Dave in October to ask if they could still plant hairy vetch.
Type: winter annual or summer annual legume Roles: N source, weed suppressor, topsoil conditioner, reduce erosion Mix with: small grains, field peas, bell beans, crimson clover, buckwheat See charts, p. Few legumes match hairy vetch for spring residue production or nitrogen contribution. Widely adapted and winter hardy through Hardiness Zone 4 and into Zone 3 with snow cover , hairy vetch is a top N provider in temperate and subtropical regions. The cover grows slowly in fall, but root development continues over winter. Growth quickens in spring, when hairy vetch becomes a sprawling vine up to 12 feet long. Field height rarely exceeds 3 feet unless the vetch is supported by another crop.
Hairy vetch also improves soil tilth and fixes significant amounts of nitrogen which can be utilized by subsequent crops. Organic Farming: Hairy vetch provides a natural source of nitrogen and forms a weed suppressing mulch for organically grown crops. Livestock: Hairy vetch with its high crude protein content can be utilized for hay, silage or grazing. Hairy vetch is a viney, cool season annual legume with stems 2 to 4 feet long. Leaves are composed of 10 to 20 narrow leaflets and are terminated by branched tendrils.