which cover crop for this application ?

I have about two months till I can plant warm weather crops; however, the weather will be fairly warm, with an occasional cold snap.

I need a cover crop that can be planted now, and be ready to kill for mulch two months from now. It has to be frost resistant, heat resistant, nitrogen fixing, and easy to kill. Hopefully it will grow a lot of biomass. It would be helpful if it loosened the soil. It would be nice if the seeds were large, so that they could be planted deeper and stay moist with less work.

Finally, the seed should be cheap, ideally found in the grocery store. I was thinking about lentils, or fenugreek.

Of course, a mix would be best.

Any ideas?

Things like winter pea and other less than table grade peas might be worth thinking about.

I'd try a type of bean plant ( legumes ) they take nitrogen out of the atmosphere and store it in their roots. When they die they release the nitrogen back into soil. To looseing it look into some kind of root vegetable. Turnips would be a option hardy easy to grow and big seeds. Don't be afraid to mix cover crops together. Just hand sow them evenly across three soil your trying to amend. I used both legumes and root crops at the same time works well.

I agree with landon, peas, cheap, big, and most animals don't really want them. And they have a harvest! Then do beans, if you want a harvest cover. If not, vet ch or clover. Finish with rye. Based off your location. Other wise, are you actually in Denver? Co has a vast array of climates. And micro climates. How much space do you have? Some people consider beans a "filler" I know I have had some spaces that I need all I can get. Sometimes responsible outsourcing for mulch is better, with succession planting and tight spacing. Is this a food forest? Or garden? Some people consider cover crops only for their mulch qualities. I use fennel, dill, cilantro, nasturtiums, arugula, and all kind of seed generous annuals as cover crops with a bonus. Kinda like a wild three sister system, with a really big family tree.

This is not a real edible crop but the plants are edible and it is used for feed.
That is the Austrian or Bavarian pea. These are small peas a bit bigger than a BB.
They are one of the most cold hardy peas.
I am broadcasting them this morning in my poultry pen areas to let the birds work them into the soil.
Sort of like running sheep over land after broad casting grains

This is a community farm. We will be doing half of it in wood chip mulch, and half in some sort of cover crop, since not all crops like a wood chip mulch. We are in a Denver suburb. We will be plowing once to get started, and need a way to quickly cover the bare soil. Mulch would take too long to haul and spread over a large area. Also, we need some nitrogen, and blood meal isn’t cheap. Spreading manure would not be safe at this point.