questions about cover cropping

I like the idea of cover cropping since it produces something from nothing. I don't do it however. Partly because I can grow broad beans over winter and when harvesting the beans all the protein is eaten instead of dug into the soil and partly I don't know much about the how to. The how to: if I grow something up to the flower stage and slash it I have 30 cm long or longer bits and pieces that is not what I want in a seed bed. For potatoes it is OK though. Even if I hoe it into the soil it is still long rough stuff. How do I cut the plants on a garden scale - whipper snipper? Or do I cover crop something which disintegrates into a slimy mass afer a week or two?

Angelika Maier wrote:How do I cut the plants on a garden scale?

You could use a type of mower called a flail mower, where the blades are attached on the end of hinges or chains. This tends to produce quite finely chopped residue, and it sounds like this is what you're looking for. Attachments for garden tractors with flail mowers are fairly easy to find, at least here in the US, not sure about Australia. Mowing with a sickle-bar mower or scythe, then raking into windrows and driving your lawn-mower over it is also an option, so long as it's too thick for the lawn mower.
As far as cover crops that tend to break down quickly, buckwheat is a common one.

I will have a look into tha flail mower.
It is as well about loosing cropping space, either peas and broad beans and harvest something or use the same as cover crop.
HOwever, I just did a bed with buckwheat, because it is too late for summer things and my cabbage seedlings went into the box yesterday, so I thought it might be a good thing to throw some buckwheat in until the seedlings are up. I could have planted some radishes but how many radishes can we eat?

Other than the Flail mower you could look at a mulching mower, these will chop things into nice tiny bits that decompose quickly and they are usually less expensive than a flail mower.

Many of the Lawn Mower companies have mulching mowers as well as mulching kits for their "normal" mowers. Ours was under 300 dollars for a 6 hp., self propelled model from Snapper.

If you're planting broad beans on a bed over the winter that you plant something else on, I'd say you were practicing cover cropping. Just because you use the "fruit" of the plant doesn't mean it's not a cover crop. Maybe I misunderstood what you wrote, but it sounds to me like you're already on your way. But, you need to plan your cover crop mix based on what your plans or needs are. If you are using cover crops for purposes A, B and D, then your cover crop mix will be 1, 2, 7 and 12. If you're purposes are for C, E, and M, then your cover crop mix will be 5, 8 and 14.  See what I mean?  If you want to increase organic matter, fix nitrogen and add copper, you may want to plant a particular mix of cover crop seed to do those things. If your purpose is to reduce compaction, suppress a pest and provide forage for goats, then your cover crop mix will be seed to do those things.

I also wouldn't think you need to have the cover crop pulverized to a fine size. Organic matter when cut to even a couple of inches in size will break down pretty quickly in a planting bed. Sometimes I find gardeners who believe they should have a their soil nearly like powder and fine granules. I encourage people to have soil that looks more like cottage cheese and chopped organic matter from cover crop can help this. You want those air spaces and "chunky" feel to the growing medium. The air and water combination in your soil is a better host for the billions of critters living and making your soil healthy.

But, repeating myself ... what you want achieve will determine what your cover crop choices are. Many people are trying to change or improve their soil chemistry and there are different cover crops mixes that can help do different things in that regard. I encourage you to define specifically what you want to achieve and then make your choices on cover crop seed ... yes, even at garden scale.

It seems to me that what you are really asking is what to do with the residue.  The residue for a season's long planting can get out of control and be very woody and difficult to plant through because of the fact that it can take time for decomposition to occur.   When you raise a crop like beans (bean seed from the supermarket which you add inoculant to would be fine) and you let the crop grow to flowering, you are cover cropping and, if you chop up the bean plant and add it to the soil, you are adding a green manure.  When you cover crop, you need to be conscious about what you want or expect the following crop to be and plan accordingly.  If you want to plant early, you can plant in late summer a crop of oats if zone 6 or above.  You can then leave the dead oats in place to help protect the soil and add the remnants in the spring.  If you want a summer cover crop but want to grow something later in the summer you can dependably choose buckwheat.  If you cut its weak stems with a hoe as it begins to flower, you will get the benefit from that.  But if you wait a bit, buckwheat will self seed and if you cut it down later, you can grow a second crop of buckwheat from the seeds of the first.  

Even some pretty  difficult crops like sudan grass can be kept more or less succulent if mowed during the growing season and it will die with the first hard frost.  You can also use an out of season crop (winter rye in spring) which needs the cold vernalization to grow  and cut it in when small and succulent (though then it acts like a green manure and won't have the longer acting soil building effects like woody crops would).

There are many cover crops out there and it makes sense to experiment with those that you can obtain cheaply.  Supermarket wheat berries, beans (but not pearled barley, etc) will all come up and give you some good effects.