I use a winter cover crop in the fall.Last spring I mowed it down and planted into it.It acts as a mulch until the ground warms up.After that I use a thick layer of straw.In the fall I mowed that down.I then used a garden fork to turn the straw under and raked the soil and scattered my winter rye and vetch seeds.I'm going to repeat the same this spring.I have seen pictures of people with raised beds putting in a winter cover crop and doing the same thing.It worked out well for me.
Just a thought I'd share.