Grapes

Should I be pruning my grapes during the summer so that more sun and light is hitting the grape clusters? I have lots and lots of leaves and so the grapes themselves are very shaded. Some taste great but others are small and sour. Is it the leaves that need the light or the grapes? Also, I have thought not to fertilize grapes. But these have been in the ground a long time. Should I now be adding some amendments?

Could it be a lack of water? We got a lot of rain this year in the PNW and I did water once on my own besides that, but I don't know how much water they need.

I don't know what kind of grapes these are. Table grapes I believe. Some are green and some are red but the red ones are all sour.

Thanks
Gwen

Pruning is usually done in the spring, while the vine is dormant. Grapes grow on last year's wood - the sprouts that were green this year will bear fruit next year. Prune away the old wood.

If you have lots of leaves w/o much fruit, your soil may have too much nitrogen.

Gwen
You need to pull or clip the leaves from around the grape clusters so the sun can dry the moisture which will help control black rot and other fungi. Also, I clip the ends of the runners if they get too long ie. hang down to the ground. The grapes that get the most sun will ripen first. I suspect from your description that they are simply not ripe yet. Also the majority of grapes set at the same time but vigorous viness will continue to bloom and set for 3 or 4 weeks thus you will have small green grapes , usually inside the vines at the same time the main crop is ripe.
I would just wait a couple more weeks and I think they will ripen OK
RED

Too late, I already picked them all! Hopefully next year. We will keep it pruned back more so more sunshine. (If we ever get any sun, that is!)

Gwen