We moved into a new home three years ago. The house had concord grapes growing. The first year we got bushels of grapes from the vines. Last year we ended up with a much smaller crop... only about two bushels. This year there is no fruit growing. I have never cut the vine back and the vine is out of control. I want to prune them back but am not sure how much to take off the vine or when the best time to prune is. Any help is appreciated.
Grapes of any sort require extensive pruning. Normally, more than 90% of the new growth is removed every year. You have to have a system in place to keep the grapes under control, and the system depends on the type of support structure used. There is much literature available regarding this topic. I suggest that you read about it and decide what system will work for you. Then you should remove most of the rambling growth during the next few years and direct the new growth where you want it. If you keep some of the current year's growth, you may be able to sustain some grape production while you rework the vines. You can start pruning right now, since you have no fruit this year. Keep a small percentage of this year's growth and remove everything that you won't need next year. This will encourage the remaining new shoots to mature fully, making them more likely to fruit next year. You probably had too many new shoots that weren't able to mature last year; so they weren't capable of bearing fruit. I prune any time I see undesirable new growth and remove the old fruiting canes right after harvest, but major pruning is normally done during the dormant season.
They are on a wire and pole system, although you can no longer see it. I will go out and start cutting back the vines today. Will any harm be done if I cut back beyond this years growth? If I prune back this years growth now , or nearly all of it, should I prune more once we hit the dormant season? Thanks for your help!
Grapes are very tolerant of severe pruning; you can cut back older wood now, as well as this year's growth. I wouldn't try anything as radical as cutting the main trunk off, but they will tolerate just about anything else. If you want any fruit next year, you should keep some of the best shoots from this year's growth. Any new shoots that develop this late in the season will not mature enough to produce fruit next year. If you prune heavily now, you will get a lot of late, non-productive growth that will need to be pruned out during the winter.
I cut it back yesterday. I left a little new growth and was surprised to see a few clusters of grapes. Some of the vines must have been 15ft long! So now I need to prune again now in the winter months? Is it easy to tell how much to prune back then? It is easy to tell now since the new growth is green. Thanks for all your help.
With a wire and post system, grapes are usually pruned using the Kniffen System, with various numbers of arms, depending on how many wires are used. If 2 wires are used, 4 arms (new shoots) are allowed to remain each year; and all of the other new growth is removed. The ends of the retained shoots are also pruned back. Do a Google search on "kniffen" to learn more about it. This will give you a better idea of how much pruning you will need to do during the winter. I prune my grapes to a highly modified Kniffen System with as many as 16 arms on a main trunk that is about 15 feet tall (growing up the face of a 2nd story deck).