Final Report for FNC13-913
My initial goal in starting this project was to expand my current wild grape vineyard with a variety of trellising methods as well as different pruning, watering, and growing methods. As far as I know this is the only wild grape vineyard in the Midwest, if not the whole of the US. I have looked for these last few years and found nothing. So there is not much information as to what the “ideal” method is for growing these vines in a commercial setting. What I was able to use for a resource however was the other local commercial grape growers in Minnesota and North Dakota and most importantly the people at NDSU.
Wild grapes vines (Vitis riparia) is dioecious which means these vines have separate sex per plant. One plant is female one is male. Regular commercial vines are bisexual and self-pollinating. Wild grapes also differ in that they are very hardy in that they can easily handle very cold subzero temps. The biggest challenge to wild grapes is the timing of harvest. The general feeling is right after first frost is the optimal timing for sugars and acid especially as to its influence in wine making.
Very little is known about wild grapes (Vitis riparia) and what they are capable of in a domestic setting. Much of what has been written about concerning them is often sparse and even contradictory, leaving more questions than answers. In my time growing them I have only met one person who has attempted to grow them on a trellising system and in that case they were neglected in favor of other varieties. Most people who are interested in using them for wine production have generally used what they can get growing in the wild.
The biggest question concerning our project is can the wild grape be grown in a traditional grape growing setting? Will the classical style of pruning and trellising be possible with wild grapes or will it be something that is harmful to the vines? There are questions as to whether or not pruning and trellising these vines could possibly shock them and stunt their growth.
My first objective was to see if growing them in a domesticated setting was even possible. Next what style of trellis would best for them? What kind of pruning would be best for them? Do we prune them in the classic manner or is it better to give them a lighter pruning? Or perhaps no pruning would be most beneficial? Again there is little to no information currently out there as to these questions in print or on the internet so this was truly starting from the ground up.
The various methods of trellising we ended up using were the double arm kniffin, the geneva double curtain, a custom overhang style trellis, and last a 9-foot fence was used as a trellis. The double arm kniffin forms a double cross with the trunk going up vertically and four arms going out horizontally forming a double cross. The geneva double curtain looks like a clothes line with the trunk going up and the cordons (arms) of the vines attached to the two wires at the top forming a curtain of leaves. The third style basically had the trunk go straight up until it reached the top and then grew on a wire fence that hung overhead. The idea is that it would reproduce the natural habit of where wild grapes naturally are inclined to grow (they generally use other trees as hosts, growing on the outside of them and eventually killing the tree.) The final 9-foot fence is simply our fence surrounding our first vineyard. This simply allows the vines to grow up the fence and create a wall of vines.
Our watering system was basically a drip system off of our well that produced 1 gallon of water per hour. The basic belief is that we shouldn't really have to water other than when we first plant so that the roots of the new vines can be established, although that can differ due to weather conditions.
Pruning was varied by the amount of pruning done. Our basic method for pruning was a cordon system which allows an arm or cordon to come off the trunk of the vine which is fastened to the wire and then has shoots growing off of it each year. Our variation in pruning was either traditional pruning in the spring or no pruning at all as well as somewhere in between.
Pest control is also something that we plan on experimenting with. The wild grape is about a third the size of a domestic grape and makes easy prey for birds. That being said birds and deer are very big problems for all grape vines. Deer can be brutal for vines. Not only do they like the fruit they also like to eat the plant itself. Our first vineyard fortunately is surrounded by a 9-foot fence which works great but unfortunately it becomes cost prohibitive in further expansions. So part of our research is finding cost effective ways in protecting our vines. We experimented with things like fish line, deer repellent, motion sensors, balloons, plastic owls and hawks, and electric fences. All had varying results.
Over the last two growing seasons the vines we initially planted for this study have only started growing on the trellising system, and so far they are thriving and forming to the given trellis system for the most part. Winter die back has made some of them start from the bottom up but most vines are doing well. Fortunately we have our vines we planted before this and with some modifications in trellising systems it has allowed us to see if each of these trellising systems is possible. These mature vines which had their first real crop in 2014 gave an indication of what wild grapes can do in a domesticated environment. Overall the vines that were trellised and pruned showed fruit that was almost twice as big in size and the clusters themselves were tightly packed when compared to what grows in the wild. The vines that were trellised but did not get any pruning had larger fruit but in that case there were clusters that were loose. The most unsuccessful trellis was the unpruned overhanging trellis which showed no improvement in comparison to the vines in the wild. The double arm kniffen trellis system had our highest yields but it was the trellis that was most used. The nine-foot fence trellis also had high yields but it was difficult to tell as to what plant was responsible due to the overgrown nature of the unpruned vines.
Pruning overall seems to have helped in the size and cluster tightness of each plant. I did not see any difference between pruned trellises but definitely a difference between unpruned to pruned. Pruning seemed to give large fruit and tighter clusters. The ripening of the fruit did not seem to be any different for the most part.
Watering was hard to get a handle on for both 2013 and 2014 growing seasons. Both season saw very heavy rains at the beginning. 2014's season began especially wet -- so much so that there were problems of chlorosis within all plants not just our grape vines. Both seasons also saw a very dry second half so I would weekly, to sometimes daily, water the new vines as well as the established vines. This being so it was hard to say what effect watering had on these vines due to the weather conditions.
Pest control was probably the most involved of the experiments. As I said above the birds and deer are great lovers of wild grapes and both years were a struggle to protect the fruit and the vines. Season 2013 saw us try a few things in the way of birds. Our vineyard #1 was on its third year and starting to have some fruit so we decided that as a test we would string fish line over the whole 10 rows in that spot. Since we had 9-foot fences, we simply connected the line to the posts and crisscrossed fish line over the whole of that vineyard. After all that work we were hoping it would work.. It didn't. The birds (usually robins and woodpeckers) had no problem navigating through the string. They quickly ate all fruit available except the fruit covered by the leaves of the unpruned vines. Since our newly planted vines have new fence around them I was a little concerned as to what would be their fate, but since they were in 3-foot tall grow tubes the vines were protected enough that they were able to grow and establish roots without being munched down to the root. It also helped that they were planted by a giant alfalfa field which held more allure to deer. By the time the vines had grown out of the tubes and up the trellis, Autumn came and the vines had hardened off. This made them less appealing to deer but I went ahead and created a fish line fence surrounding the new vineyard. I was told by many gardeners that this was an effective way of keeping deer out. They try walking into vineyard feel the fish line and it spooks them. I checked over the winter and that definitely seemed the case. There were deer tracks all around the vineyard but nothing inside.
During the winter I also experimented with scented soap hanging in bags from the trellis in certain areas but this seemed to not have any effect. Especially when spring came and I took down the fish line. Then I started to see deer damage to the vines.
I also tried motion sensor lights/radio which would turn on when a deer moved in front of it. Alone it seems to work as good as the soap. Unfortunately the fish line fence wasn't going to be practical for working in the vineyard. I talked to another vineyard owner in Forest Lake, MN who convinced me that best way to keep deer out was an electric fence with one or two wires. From there you put pieces of electric tape on the wire every 10 ft. or so and then smear peanut butter on that tape. What it does is attract the deer to the smell of the peanut butter on the electric tape and when it goes to take a taste or sniff it gets zapped. It effectively trains the deer to stay away from the fence. So that Spring 2014 after taking down the fish line and seeing deer damage to the vines I put up the electric peanut butter fence and found that it worked great! Throughout the season I checked the vines and never saw any damage after the fence went up.
Birds for 2014's growing season did not let up and in fact they started early as I saw ripening occurring mid-August. This year I decided to go with the tried and true method which was bird netting. This bird netting is considered to be the most fool proof method you can use to protect your vines from birds. So when I saw birds starting to attack the vines in mid-August I decided to cover all vines with that netting. It took a day with one other person to put up the bird netting. The netting is simply put over each plant and then clipped at the bottom. The double arm kniffin was the easiest trellis to fit the net over while the rest took some stretching. The net itself can tear so we had to be careful. For the most part the netting was very successful with about 10 birds getting into the net over the month and a half they were netted. If they did get in they were either let out, dispatched, or as in the case of two birds so entangled in the net they died. Unfortunately the netting didn't protect all of our grapes. Some were eaten by birds that made it into the net and other were able to use the wind to their advantage as the grapes poked through the netting on windy days. But by and large the netting was the best protection yet.
I also used some other deterrents such as reflective tape, old CDs, plastic predatory birds (which I move every few days to keep the birds on edge) and balloons. All of these were inconclusive in their effectiveness. The grapes proved to be too tempting for the pressure to totally stop.
- Wind damage to bird netting.
- Wind damage to bird netting. You can also see reflective tape we used to scare away birds.
- Vines under bird netting.
- Newly planted Riparian Vines Summer 2014
- Plastic hawk along with bird netting in vineyard
Impact of Results/Outcomes
The overall accomplishment of this project is that I can say for sure that wild grape vines (Vitis riparia) can be grown in a domestic setting. They can be pruned and trellised and have varying responses to how this is done. Overall the Geneva Double Curtain and the Double Arm Kniffin both have worked very well as trellising systems as well as our 9-foot fence trellis. The pruning of these vines overall showed fruit clusters that were much larger and were more tightly packed than that of a a Riparian vine in the wild. So the results did show that some of these methods definitely can help create a bigger and more plentiful fruit. Having only one year to have seen a real harvest I can only draw so many conclusions, but the main question of whether or not Vitis riparia can be grown in a domesticate setting is a resounding "Yes."
Educational & Outreach Activities
As part of our outreach I set up a couple websites
More directly we had a group of 15 people come out this harvest season 2014 and have a harvest party. These people with varying amounts of experience with growing grapes came out to help us with our harvest and learn more about what we were doing. Some people had never been in a vineyard before and some had. We supplied food, coffee, wine for the event and people learned about what we were doing. (see pics below) Overall the whole thing took 8 hours to complete the harvest (we started at 7 a.m.) stopping only for lunch. The other exciting part of this was we were able to get the grapes to South Dakota winery to make our own wild grape wine!
As I have mentioned before there is very little info about how Vitis riparia grows in the wild let alone in a domesticated setting. So far I have only had a few years of growing them in a domesticated setting and one real harvest so we have many more seasons to go until we can truly say "What works" but so far so good. The question as to what are the best methods for this cultivar are still up in the air but what I have seen so far is highly promising. Ultimately I think the greatest contribution of this study is the information on not only the growing of wild grapes but also growing any variety of grapes in this growing zone.
The next step from here is to further investigate pruning methods, trellis systems, and watering for these vines. This week Harlene Hatterman-Valenti from NDSU suggested two different approaches in pruning and trellising that may help with getting more fruit per vine. This is one of the major challenges for wild grapes.