Converting to VSP

[NorthSlopeVineyard]

I'm currently growing Marquette and Petite Pearl on a 4-arm trained system at about 36" and 60" on 6' spacing, with permanent cordons and spurs. This works great for the PP, but the Marquette is too vigorous and the shoot thinning is somewhat overwhelming. In addition, the Marq will throw 12' long running shoots if I let it. I want to convert it to VSP as a way to summer thin both the fruit and foilage, and get better sun exposure. Also, the Marquette seems to be more upward growth oriented. I make plenty of fruit for my needs, so the reduced yield on the VSP isn't a concern.

Does anyone have any advise on this? Should I just prune off the upper cordons this spring, and adjust my trellis to make a VSP system?

 

[JimInNJ]

Wouldn't cutting it back like that encourage even greater vigor? Would something like GDC or a lyre trellis be an option to absorb the vigor? Or pulling every other plant and growing out the cordons to fill the gaps?

 

[BigH]

I'm currently growing Marquette and Petite Pearl on a 4-arm trained system at about 36" and 60" on 6' spacing, with permanent cordons and spurs.... I want to convert it to VSP

Is your 60" wire at the top of your posts? Do you have the ability to lower the bottom wire? I had La Crosse on a VSP with the fruiting where somewhere around 32-36" and the top catch wire at 72. I felt like I didn't give the vines enough vertical room. Granted, La Crosse is reported to be more vigorous than Marquette (mine has been).

Another concern is whether cutting off the top cordon will leave you enough buds to control vigor next year. If you proceed, consider executing your gameplan over two seasons. Convert each vine to VSP in one direction, and 4 arm kniffen in the other (guess that makes it a 2 arm kniffen). Since you are dealing with canes, the VSP side would technically be considered a Guyot system for one season until you have spurs.

Lastly, you might want to consider going in the other direction and converting to TWC. TWC will de-vigor the vine more than VSP will, and since you are having vigor problems with vines at 6' spacing, I think you may want to leverage that. See this old thread for more info: https://www.winemakingtalk.com/threads/am-i-choosing-the-proper-training-systems.37792/

This article may also be of interest : http://northerngrapesproject.org/wp-content/uploads/2014/04/April-8-2014-NG-Webinar.pdf

H

 

[GreginND]

I would also recommend TWC. Marquette does really well in a downward growth and as H mentioned, this can help reduce vigor. And you can trim the canes off near the ground if they get too long. No need to have fancy guide wires and it is not that difficult to do some leaf pulling and trimming on the top to let sun at the fruit.