It's hard to imagine putting in too much organic matter. You could easily put in two tons of alfalfa hay on an average field. In two months, that organic matter would be virtually absorbed by the soil. As for manure, he recommends horse, cow, rabbit, or chicken in that order. Because our soil tends to be low in nitrogen, blood meal is highly recommended as well.
Yellow tips can signal a nutritional problem or that the garlic is dry.
A short story, and then the recipe. For years we'd go down there and hit all the clubs. We could never find out what was in it. Pour out the water and leave them in the pan a couple of minutes to dry out. The Greeks swear that you have to do this by hand, but I've done it with a blender and it works fine.