Pruning is one of the most important practices for grape vine control and care. Cutting back grape vines trains the plant to grow to the required shape and form. Pruning also promotes grape growth and regulates bud growth in the spring. Most important, pruning helps prevent the transmission of vine diseases that thrive on old and dying parts of the vine's wood. Pruning must be done every dormant season to encourage fruit growth and the highest yield during the growing season.
Remove any dead or broken vines that are hanging to prevent the spread of disease and to promote new growth on the vine.
Separate the other vines as much as possible to get a view of what requires cutting and what vines are OK to leave.
Keep any vines that are pencil thin and mahogany in color--these are healthy vines that will grow in the next year.
Cut away any vines that have discoloration--yellow is common--as they are most likely dead on the inside even though they appear alive.
Remove older canes from the vine that are hanging down over the top of the trellis to promote new growth. If two canes are growing from the same node, cut away the older of the two.