I am planting grapes in my backyard in the spring. I have about 1 foot depth of good soil and then the subsoil begins to slowly show with sandiness and yellowish in colour. I am aware this soil is not good for optimum results. My neighbour has not had great success with his grape vines due to the same fact. He told me his soil is not that good. He has about 6 inches of good organic soil then subsoil begins to show yelowish and sandy. I am going to ammend my soil to maximum 4 feet in depth...in the spring to increase better results and success with the grapes. Basically I will keep the good soil I have now by putting it to the side and then dig out the poor subsoil and discard it. Going down to 4 feet in depth. Then will add loam, manure e.t.c. I feel this is just, anyone else share any views on this?