Winter cover crop zone 5b

I want to plant a cover crop in my garden. My purpose is to build soil and stop erosion. I was thinking of hairy vetch. In zone 5b with the first frost date mid September is it too late to bother?

So I’m just a newb here but I’m in zone 5b too and I just planted hairy vetch (like last week) on my new hugel bed to stabilize the soil and overwinter it, and it’s starting to come up now, so probably not too late?!

I am in 7b so it over winters here.  If conditions do allow it to overwinter it will produce a lot of biomass in the early spring.  I use it to improve my fields. I cut it with a scythe when it has set seed but the seed pods have not opened yet then spread it out where the grass is not growing well and it seeds itself to start growing when the rain returns.  Seed can be saved by drying it in a tarp to collect the seed.

Tillage radish is great for that very thing as well, and this is the right time of year for it.  I had really great results with it in zone 4b.

Our average first frost here is mid September as well (we think - in a microclimate and still figuring it out), and the wild vetch is currently going to seed. I'd say it's a perfect time to plant.

I like rye as a cover crop and food crop. I don't plant it until we get precipitation in the fall, so that could be anywhere from mid September to mid November. It usually gets planted well after first frost. As long as you get a few days of weather warm enough to germinate the seeds, it'll be good.

A late planted mix that I use here and should work in most areas is cereal rye, crimson clover, fixation balansa clover, hairy vetch, common vetch, winter camelina and rapeseed. They might not all survive the winter in every location, but most should make it through in even the coldest locations in the lower 48. Ideally you'd want to plant this mix at least a few weeks before the average first frost in the fall, but some species like the rye and camelina can even be planted after the first frost and still do great.

So true Travis. I planted rye the last week of December a couple years ago. It never got above freezing a few weeks later and it still did fine.