From Ecology Action
Answer: Thanks for inquiry regarding the best types of organic fertilizer to use in your garden. Alfalfa meal is often good. Bone meal is problematic because of the possibility of introducing Mad Cow disease. Wood ash can be good if the magnesium level in your soil is not too high. You may want to consider having a Timber Leaf Soil Test done to determine the status of minerals in your soil. If you have How to Grow More Vegetables you can find their contact information in the bibliography under “testing.” Or, if you prefer to look online, you can go to www.timberleafsoiltesting.org. You would want to order the basic/trace mineral package. Having this information saves gardeners years in improving their soils.