Muscadines can be grown by the organic method in Georgia assuming you do not have a serious problem with grape root borers and you select the most disease resistant cultivars. Even so, losses from fruit rots may be high in some years when heavy rainfall occurs in late summer during the ripening season. Research has been conducted by the USDA in Georgia in an attempt to find synthetic fabric mulch barriers for the control of graperoot borers. Contact your county Extension office, they can obtain the latest information for you on this subject.
To fertilize muscadines using the organic method you first need to determine the deficiencies in your soil via a soil test. Then determine the nutrient content of the organic fertilizer source you have available such as dried cow manure. This can be done via your county Extension office. Using your soil test report and information on the amount of nitrogen needed from the fertilizer section in this bulletin, the amount of organic fertilizer needed can easily be calculated. For instance, mature muscadine vines need about four pounds of 10-10-10 fertilizer as an estimate for their spring fertilization. This is 0.4 pounds of actual nitrogen. Dried cow manure often contains about 2% nitrogen (test the content of your manure source, manures vary greatly in their fertilizer content). Therefore, you need about 20 pounds of 2% nitrogen cow manure spread evenly under the vines to provide .4 pounds of nitrogen. If you are going to grow organic muscadines, make sure the post type you use is approved for organic growing.