Hampshire,
United Kingdom 
i am making a elevated garden about 45" higher than the current level , i have a few grape vines which have been established for 1 year . Ci just add the extra level of soil / compost to the existing level without re-planting the vines
2 Oct, 2010
Previous question
45 inches is too much to expect good results, what you will get is new growth from below the new ground level which will re-establish new canes to rods in the long term. Can you form a hole round each vine and fill it up 9 inches each year then any new growth can be cut back.
3 Oct, 2010