last spring i planted king of the north and marquette grapes for fresh eating. i trellised them each seperetly on a 5 by 8ft.cattle panel staked with 3 heavy 5ft t posts. they grew 2 shoots off of the main vine and have reached the edges of the panel by last fall. ive read so much confusing contradicting info on training grapes i dont know what to go with. should i just keep what i have now with 2 shoots across the top and stop the vine from spreading down the sides? do i allow 2 lower shoots to start a 2nd level below the top one? and for managing the amount of sprurs and buds its got my head spinning. any and all advice is appreciated. i want to keep this as simple as possible. i dont need commercial amounts of crops just a decent amount of grapes off of a healthy trimmed vine. the panels run east to west and the prevailing winds usually hit it from the NW. thanks.
Typically grapes are pruned using the Kniffen system or cordon system. I use the Kniffen system. The general rule on grapes with the kniffen system is to prune heavily leaving only 40-50 buds left each Spring and remove the rest. On grapes you need to heavily prune and take off 75% growth each year. You want to leave canes from the previous season that are about pencil thickness in diameter for best fruiting. You also need to leave renewal spurs for next years crop.
I have my vines as a 4 arm Kniffen with bottom tier at 3’ and top tier at 6’. The top tier has the best and most heavy fruit production. The bottom tier shades out. If you only have 5’ height on your posts, I would just go with one tier.
Cordon pruning is way different. I have never done it so no comment on how.
No matter how you prune the main thing is to remove excessive growth and keep younger shoots for best production. Trim the young shoots back as they can be 8’ long from just one growing season.
The easiest way is spur pruning vs. cane pruning.
With sprur you form a “T” cordon. Kinda what you have now. All new canes on this cordon are used for fruit. let them grow and fruit. During dormancy cut the one year fruiting canes back to 2 buds and let them grow out next year, and keep repeating the process. It’s easy. A few little nuances I left out.
Study this
https://www.google.com/search?q=spur+pruning&client=opera&hs=QYy&sxsrf=ALeKk03kGWelrSENsrNKksN6klT48j_n1A:1616082741925&tbm=isch&source=iu&ictx=1&fir=Vi1RU5AKnAgKfM%2CdtlOPs13jjt6qM%2C_&vet=1&usg=AI4_-kRS9PzpT3HbTRPQuJ3bLE8fTl6Vqg&sa=X&ved=2ahUKEwiO3YmumbrvAhWDVc0KHSoeDzQQ_h16BAgQEAE#imgrc=Vi1RU5AKnAgKfM
I much prefer it.
For covering a trellis or arbor, I’d basically cut it back to a couple buds at planting…and then let 'er rip! (And not over-think the pruning if you want it to cover a fence panel).