Gardenfan:

I grow concord grapes. When I plant out young bare-root or potted plants or rooted cuttings, I put in a temporary stake at each plant. Usually a 1.75" diameter wood stake that I get free at work as they burn them as a waste product. I like to prune my vine to only 1 leader and tie it to my stake. My goal is to grow it as a single stem to the top of my 6' stake and remove all side growth except at 3' and 5.5' where my wires are for my grape fencing. I raise mine following a 4 arm kniffen system.

Concord can be grown using a 2-arm kniffen, 4-arm kniffen or cordon pruned. All these systems work. I guess the main thing for you to do is to pick out how you plan to prune them and have a decent strong trellis structure to support the weight of the vines. My concords as 4-arm kniffen easily grow canes that are 10'-12' long each year!

I have seen people growing concord with 2 stems and that works too. Again the big thing is to support the vine with a strong enough trellis and properly prune so you do not have too much old wood and too many buds. With my system I prune off all canes so the past years growth on the lateral branches are trimmed to a total of 40-50 buds in spring per vine.

Where you let your vine branch on the main leader is based on the trellis structure you are using and the pruning method you choose to grow them with. It is not as important as remembering to prune all new wood back in the dormant season so the vine is not too big with too many buds that are allowed to grow and fruit.

You will find that grapevines are very forgiving. If pruned wrong they are easily corrected in the following years. Most home growers I know don't even prune them every year. They just let them go. When they get too big and stop bearing lots of nice sized fruit, then they give them a hard shear back to regenerate them (the haircut method). This gives them little to no fruit crop the following year but then they are back in production for a few years until they shear again to regenerate. The BEST fruit will come off of wood from the previous season that is about pencil thickness in diameter. Fatter canes or thinner canes would be more of a priority to remove when it comes to pruning when you have to make a choice on what to save and what to prune.