C:N Ratio Calculator For worm composting, conditions are generally ideal with a carbon-to-nitrogen (C:N) ratio of between 20:1 and 35:1. Unit Ounces Pounds Grams Kilograms Garden waste Vegetable scraps Food scraps Manures Fruits Coffee grounds Grass clippings Fruit waste (e.g. banana skin) Peat moss Leaves Straw Shredded newspaper Wood chips Shredded carboard Sawdust grams ?:1