Test and amend the soil according to the soil test directions a year before planting. Two to three weeks after planting, apply 2 ounces of 33-0-0 to the plants, taking care to keep the fertilizer 1 foot away from the vine. In subsequent years, apply 4, 6, or 8 ounces of 33-0-0 per plant or 1 to 2 pounds of 10-10-10 per plant before the buds start to swell in the spring. If vines are too vigorous, omit nitrogen for 1 to 2 years. Test the soil periodically (every 3 to 5 years) and maintain a soil pH between 5.6 and 6.4.