Grapevining Pruning for Geeks (or more accurately, by a Geek?)

Today was a wonderful sunny and calm day, and I decided to take a break to enjoy the weather for an hour or so.  First I filled a wheelbarrow full of weeds and cuttings of dead twigs and such, and then I decided to be daring, and try to prune my grapevines.

The grapevines are still quite young, having had my first crop of grapes last summer.  So this is the first time  really "pruning" them.  In previous years, it was more of selecting the shoots which I would train on the trellis.  I have read lots of different descriptions on how to do it, and have been adequately confused by the terms and which of the Kniffen systems to use, and about the old wood vs. new wood, and how many buds to leave, to use as next year's lateral branches, or whatever.  But I think the basic concepts which I understand are these:

1) Trim back quite a bit, since grapevines grow like crazy.  I think I read somewhere that one should remove some 60% to 80% of the wood.  Well, since mine are quite young, I was aiming for more like 25% to 50%.
2) Train the trunks vertically, the main branches horizontally, and then the offshoots (vertical, for the most part) from these are the ones which will bear the fruit.

One of the descriptions mentioned tagging (they tied a bright cloth onto) the branches which you want to keep, and then cutting away the others.  So being the geek that I am, I decided that it would be even better to use one of the kids' paint sets (you know the ones, the sets of one-time use primary colours which seem to come with all sorts of art kits) to mark the branches.

I was very pleased by my painting technique.  I have 3 main vines, so I decided to mark each vine with a different colour, to figure out what tangled branches belonged to each one.  Here is the vines with the paint markings, before pruning (click any photo for a slightly closer view):

Since I found out that I had 3 varieties of grapes, and one bore the most fruit, I discovered that the middle one (marked in red, and also on the upper branch in white) must be that green grape which was great for juicing.  It had an overwhelming number of extra branches, whereas the yellow one on the left (which must be the dark grape which bore only one bunch) and the blue one on the right (which must be the delicious green eating grape which only bore a few bunches), these vines didn't have much branches at all.

After painting the branches I wanted to keep, it was easy to prune out the others, since I could quickly trace them back to which vine they belonged to.  If they came off the red one, they were chopped.  If they came off the yellow or blue one, I evaluated more carefully whether I could also keep and train them onto the trellis.  So in that way, my pruning should even the score somewhat, and hopefully give the other two grapes a chance to bear more fruit this year.

I am very pleased by the result so far.  I could tweak a bit more, but the job is for the most part done:

Looking a little closer, the "yellow vine has very few lateral branches, but the one on the very left makes its way along the back of the shed.  There may not be enough light there to bear good fruit, but I left it on just to give it a chance to try:

The "red" vine ended up having also a "white" branch (which is a bit redundant, but I decided to keep it anyhow), and a smaller offshoot from the trunk, which I ended up marking "green", and keeping it also, mainly because it has made its way all the way across to the front (porch) of the shed, and I think I'll try to figure out a way to support these branches - they'll look pretty cool if they ever bear fruit:

The "blue" one had sent a long branch along the top to the left.  Once I pruned enough to free it, I flipped this over, to be along the right, where it has more room to itself.  Then I kept all the other branches too, bringing them in line with the support trellis.  The one along the bottom which is bumped up, continues up and along the underside of the roof in the porch also, so I took care to keep that one also:

I may be a geek, but I am very pleased by the result.  The true test will be when the vines start to grow and fruit this summer, and I'll be watching carefully to learn more about them so I can do an even better job pruning them next year.