Check out the Johnny's Selected Seeds catalog section on cover crops - they have great info and varieties and suggestions there.

Plow, till, seed buckwheat. Let it grow to almost shoulder high. Cut, mulch, till back into the soil and seed with high energy pasture mix. The result was astonishing. My pasture went from shit to alpine meadow in one year.

Tilled it under, then planted my Tomatoes in the spot. It seemed to work very well.
My next door neighbor did Winter Rye one Year. The Spring was very wet, so he wasn't able to till it under until June. He said it was like trying to till Barbed Wire. That was the last time he tried that.

They just cut it down and left it in place and dug holes for their crops.

This was the other article I read yesterday about it:
http://www.organicgardening.com/learn-and-grow/pay-dirt-fewer-weeds-less-labor

Plant corn, zucchini, and beans next to each other. The corn grows tall, provides the beans to grow up the corn stalk, zucchini has large leaves that provides shade to the ground.

I have raised beds, 4 x 12. Turning them over with something tall like a grass would be difficult to impossible. Even with clover, I think I might need to rent one of the little cultivator type tillers. So far haven't had the courage to try that.

What was unusual about this method was that you don't turn the cover crop over. You just cut it down and leave it in place. Here's the other article I saw yesterday. Maybe a better article than the one I posted above:

http://www.organicgardening.com/learn-and-grow/pay-dirt-fewer-weeds-less-labor

I thought any cover crop needed to be tilled in or it would keep growing. That is what would be an issue with grasses. I had read about leaving clover as a living mulch, but would worry about keeping it from blooming.

Interesting thread...thanks for bringing this idea up.

It would sure seem like it would and would compete for nutrients and water, but at some point, it must die back I guess. I don't know if it's after a certain point in it's lifecycle it doesn't regrow or what. I grow a lot of different vegetables, so some go in in very early spring, and I'm not sure if the cover crop would interfere with early vegetables or not.

I might have to try this in some part of my garden. I bought straw this year to mulch and the straw had so many seeds some of my boxes looked like wheat fields if I hadn't weeded them for a few days.

http://www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition/Text-Version/Nonlegume-Cover-Crops/Annual-Ryegrass

https://en.wikipedia.org/wiki/Lolium_perenne



http://ryegrasscovercrop.com/wp-content/uploads/2011/08/2011-Annual-Ryegrass-and-Cereal-Rye-compared.pdf

Now, you have 3 choices.

Over the winter, I use crimson clover (not to be confused with red clover - which will be a bad idea to plant in your garden) and sometimes fava beans. I usually will turn in the whole plants by hand in the spring a few weeks before planting, giving them time to break down in the soil. For warm weather, nothing beats buckwheat.

It's important for soil health to always be growing something (bare ground is no good), so if you're not going to be growing anything in a plot for a while, plant a cover crop. During the growing season, buckwheat can go from seed to turn-in in less than a month, making a bed ready to plant again in potentially 5 weeks.

Cover crops will suppress weeds, break up clayey soil, fix nitrogen, and raise the organic matter content of your soil. But don't be fooled, the nitrogen fixed is not enough to replace proper fertilizer. You still need to fertilize. There's no reason not to cover crop in my opinion, but you do need to be careful what you cover crop with and be aware of its behavior.

For example, if you let buckwheat flower and start to set seed, the stems will turn woody and won't rot very easily, making your bed unplantable (or you'd have to just mow it and remove the green matter, letting the roots rot, which would be fine but it's nice to get the green matter in your soil to raise the organic matter content). Generally same thing goes for crimson clover or favas, although with favas you can let them go to seed and produce a crop if you like.

I live in a mild climate where I over-winter a lot of veggies, and I'll toss crimson clover seeds in those beds with the veggies (kale, spinach, broccoli, lettuce, carrots) and let it sprout in the fall. The clover will be non-competitive till spring when the veggies are just about done, the clover takes over, and then I turn the whole thing into the soil and let it rot.

If you live in a colder climate with hard-freezing winters you might need a different strategy. Here in the pacific northwest, if you left your garden bed bare all winter while the rains pounded on it, the soil would be leeched of nutrients and totally compacted in the spring. A cover-cropped bed is soft and healthy.

http://www.organicgardening.com/learn-and-grow/pay-dirt-fewer-weeds-less-labor

Edited my original post to include that.

I had heard of cover crops that you dig in, but in this method, they just cut it down and use it as mulch basically, and only dig it up in the spots they are planting. In Colorado, our big problem is heat and lack of moisture, so a mulch is almost a necessity.

I only plant in the rows after I have finished growing some veggie crop, or grow into the winter, when it will die-off from frost. I find that after it composes into the soil, it leaves a nice texture, making the soil have a more soft feel. Mostly I turn my soil with my hoe, so makes it easier. My soil had been a mostly heavy red clay, but seems to be less heavy. I tried two types of carrots this summer, which was never on my list previously, thinking the clay too dense to penetrate. I grew a shallow type,(chantenay) which did well. But I also planted a type that grows 6" or more, and they also produced well. I also grew alfalfa as a cover crop, but found it harder to turn by hand as it roots pretty deeply and will winter over. The alfalfa leaves a nitrogen fix in the soil, where the buckwheat doesn't.