After your first season with grapes, you will need to train them. Start by staking them to ensue a straight, mature trunk. You will need at least 2 heavy wires strung across for support. You first wire should be 36 inches above the ground, and your second wire should be 60 inches above the ground. Train your grape limbs to these wires. One limb in each direction on either wire, trimming back everything that falls below or between those wires. When trimming, remove last years limbs, grapes grow on the current seasons new growth.
Prune old and neglected vines in stages only. Select a sturdy cane originating near the base of the plant. Cut it back to three to four feet. After this cane completes its second growing season, cut off the old trunk just beyond the attachment of the renewal cane. Old, neglected, or improperly pruned vines have too much wood. When pruning, cut as much of the old wood as possible. This encourages the growth of new wood near the main body of the vine.
Harvesting isn't as simple as you might think. Don't base it on color. Just because their color is right, doesn't mean the flavor is. Always taste the fruit before picking a bunch.
Feed your plant at the beginning of growing season with organic fertilizer at a rate of 1 pound per plant. Do not use anything with herbicides in it and make sure that you don't not use any product that contains 2,4-D anywhere near them. (That product is used to control dandelions).