I really appreciate your response. Thank you for the tips.
Regarding the funny structure, I got it in my head from somewhere online that a 4-arm kniffen would both produce well and look great. I've since changed my opinion on this since apical dominance makes the fruit production inconsistent, and I was considering doing only 1 or 2 cordons in a more typical manner. You've pretty much cemented in my mind that this is the right way forward.
It's a bummer that I'll lose 2 years on this, but that's just how growing grapes goes. I was nervous to enter this hobby when I started, but it's been 4 years since my first planting already and it seems like time just flies.
Now regarding fertilizer, do I stop after the vine is well established after a few years? I keep reading that grape vines don't need fertilizer, and that excess nitrogen can seriously harm cluster production.
I googled 4 arm Kniffen and it looks like you could still pull that off with some patience. This is a great illustration of how you can approach this:
https://pubs.nmsu.edu/_h/H303/
So essentially, your goals for the coming seasons are as follows:
2023 Growing season - allow the currently green lower shoots to grow as long as possible.
2024 Pruning - prune off all but the largest cane that grew past that mid-level wire. Tie the cane straight up on that mid wire and cut off the cane about 4 buds above the wire. (personally, I carefully nip off the lower buds on the trunk below the wire when doing my dormant pruning, leaving only the top 4 to 6 buds, however, you can instead just pull off those suckers when you see them break to ensure that all of the 2024 growing season is spent growing the top 4 to six buds into laterals)
2025 Pruning - choose the best 3 canes, one that reaches up to the top wire, one that extends left on the mid wire and one that extends right on the mid wire. Tie each cane to the wire. Cut off all but 4 to 6 buds at the top wire and nip off the buds between the middle and top wire on the vertical cane. Cut off the ends of the left and right cane at the post or halfway to the neighboring vine. Typically, this is a span of about 4' on each side.
2026 Pruning - Spur prune the horizontal cordons on the mid-wire. Choose the 2 best canes on the top wire to extend out left and right, tying them to the top wire and cutting them off at 4' or so (same as the mid-wire horizontal canes).
2027 Pruning - spur prune all 4 horizontal arms.
In the plan above, you will get grapes from the first 2 horizontal cordons in the summer of 2025 then you'll get grapes from the top wire cordons in the summer of 2026.
Try not to get discouraged, there will be many challenges ahead, including in the winemaking process which is a whole other animal. Just stay determined and patient.
Personally, I'm a bit hesitant to weigh in on fertilizer with any level of certainty. The reason being, I think just this year I've finally figured out what my grapes need. But it's circumstantial depending on the varietals, the soil, the weather in your area, etc... All I can really advise is to tell you what I do and allow you to take from that information what you will. All the serious viticulturalists take Petiole and Soil samples, have them sent to a lab and make nutrient decisions based on the results. I personally, have yet to do any of that. Initially, I fed my vines Two Cups of 5-5-2 Dr Earth fruit tree fertilizer each spring before bud break for the first few years as I didn't know any better and that's what the nursery staff advised me to do. The vines all grew fine, but not exceptionally vigorously. Then when I started getting yields of grapes several years in, I started getting a lot of problems. This included the late summer death of many of my vines. It was then I started digging a lot on the internet and asking the local vineyards where possible.
What I've now arrived at is as follows:
Before Bud Break (March to May):
1 tbsp Potash 0-0-60
1/4 lb. Triple Super Phosphate 0-46-0
After Fruit Set (When berries reach 1/4" in size):
1/4 lb. Calcium Nitrate 15.5-0-0
Post Harvest (After you harvest all fruit):
1 tbsp Potash 0-0-60
1/4 lb. Triple Super Phosphate 0-46-0
Post Hybernation (After the vine drops all its leaves):
1/4 lb. Calcium Nitrate 15.5-0-0
This plan appears to be working well as my vines are quite healthy, with plentiful large clusters and dark green leaves so far. That said, I am seeing some of the basal leaves showing some yellow chlorosis now that they're approaching verasion, which I'm not entirely sure if that's a magnesium issue or not, but it has happened every year and I've still gotten a yield.
My understanding is that you should always fertilize your vines if you are harvesting their fruit. I believe this comes from the idea that in the wild, the fruit falls off and breaks down in the soil around the vine every year, which allows the vine to maintain a cycle of its own nutrients. But when we take all that fruit off the vine each harvest, we're breaking that cycle. I think in story above is testament to that idea, given that my vines were undernourished with my old fertilization plan once I started taking the fruit, plus the fact that fruit production is very taxing on the vine, so it requires more energy to stay healthy when producing a yield.
