Hi Jason we are in zone 4 in the interior of BC and I had the same question! We grow broad acre grains and like you wanted something to cover the soil after harvesting but there is so little growing time between mid Aug and snow/freeze up in November. This year we planted our first cover crop and tried a 5 way blend of Oats, Berseem clover, Austrian winter peas and annual Italian Rye-grass with a few turnip to see what might establish well enough to give us some biomass and hopefully fix some nitrogen too. The oats and rye-grass were very vigorous but the peas, clover and turnip only got a few inches high. It didn’t help that we got a very early cold and snow in Oct, which it survived, but it stunted the peas and clover. They never really got going. I would say the oats slowed down the weeds and will be a good mulch over winter. I planted this combination so everything would winter kill. We are organic and felt terminating in spring might be difficult. We have had good luck with straight rye other years over-wintering well. But we would have to till it in to terminate it and then it’s tight to get a new crop in and catch spring rains before it gets dry in our area. We are dryland.

I would be super interested in any experiences other folks have had with legumes planted in the fall in our cold zone. Any actually get established enough to survive winter or if not, fix enough nitrogen to make it worthwhile?