Hi, I'm Daniel Penselin, and this is how to prune old grapevines. The things you will need: grapevines, gloves and garden shears. First, you can start by examining your grapevine and removing any dead or diseased vines. Do this by using your garden shears to snip the vine near the root. Remove any suckers that may be growing up from the bottom of the vine. Snip all intertwining vines and leave the strongest and healthiest of the two. And finally, check the vines at least weekly for vine quality and health; and that is how to prune old grapevines.