Land preparation should begin the year before planting. Prior to the application of the lime and fertilizer recommended from soil test results, perennial weeds and grasses should be killed.Weeds such as honeysuckle, brambles, johnsongrass, and bermudagrass are relatively easy to kill before the vineyard is planted, but more difficult and expensive to kill after planting. Your county Extension agent can make helpful suggestions for using recommended herbicides.
After the troublesome weeds have been killed, fertilizers and lime recommended from soil tests should be incorporated in the soil. Raise the soil pH in the top eight inches to 6.5 before planting. Dolomitic limestone is preferred as a liming material because it contains magnesium an element necessary in large amounts for maximum growth and production of grapes. Phosphorus should be tilled into the soil before planting if it is deficient. Phosphorus moves very slowly downward in most Georgia soils.
Once the lime and fertilizer applications have been made, prepare the soil as thoroughly as you would for planting seed.Harrow the field to incorporate the lime and fertilizer.Use a bottom plow to turn the soil eight inches deep. Harrow the field again. Subsoil as deeply as possible (usually 20-24 inches) down the row and across the row where each plant will be set. If the soil is extremely hard,subsoil the field every two or three feet in both directions. Do not subsoil when the soil is wet, this creates a glazed trench.Harrow the field again to smooth the soil and encourage limed top soil to fall into the soil trench.Recent research from Mississippi indicates a large augered planting hole (24 inches in diameter) results in the most rapid growth of young vines in heavy soil. In sandy soil, a through subsoiling provides good results. Preplant subsoiling should be conducted on all soils, even if an auger is used to make the planting hole, to enhance long term root growth.