Hi John,
I can’t see the logic in growing a green manure for the sole purpose of adding it to your compost bin.
One of the main reasons for growing a green manure is to retain nutrients in the soil over winter which will then be returned when the green manure is dug back in. In addition some green manures (legumes) will add additional nitrogen to the soil which the plants extract from the air.
Growing a green manure and then removing it leaves the soil depleted and you will then need to add manure/compost for following crops.
I personally don’t use green manures any more but have had excellent results from them in the past. I now go with Charles’s method of adding a layer of compost/manure which I then cover until I start planting/sowing again in the spring.
Don.