Q. My grapes which are about 20 years old and produced grapes last year. I added 4" of mulch dirt and feed with Fruit and Nut fertilizer in spring. There were no grapes this year and the leaves look mottled.
A. From your pictures the leaves look pretty normal with a little bit of wind damage. I suspect that the grapes were either not pruned correctly so that fruit was produced from last years growth (spur or cane pruning) or there might not be enough light.
You will need at least 6 hours of full sun to produce much. Less than this will result in very weak fruit production or no fruit production. If light is a problem it will only get worse as the tree gets larger.
|This is plum, not grape, but demonstrates the tearing damage that wind creates particularly on soft new growth.|