I've been doing this successfully for many, many years. I use beans and all kinds of cow peas in spring and summer and use clovers, vetch, and small grains in fall and winter.
My garden soil is NEVER, EVER bare...if it isn't producing crops, it is being replenished by N2 providing cover crops. My recently harvested onion row is now growing purple hull peas, my recently harvested carrot and radish row is growing crowder peas, and my recently harvested potato row was planted today in blackeye peas. These will be allowed to grow to mature peas, then shredded and allowed to reseed and grow again. I've done up to four generations a season of N2 fixing in a growing season this way without ever adding seeds after the initial planting. Imagine the amount of N2 and green manure and effective weed protection this provides. This is stuff that money can't buy and no amount of artificial fertilizer can equal.
People ask me how to grow 4 pound onions...I tell them N2 fixing, soil building, weed preventing cover crops.
Works for me!