Winter Wrap Up in the Vineyard
Blog #4 3/2022: Table Grape Varieties for Subtropical Hawai'i Trials
Pruning the Vineyards, Making and Planting Scions, Winners of the past 7 years
Photo Below: Before Pruning Winter 2022
The Fall of 2021 saw a shift in the weather pattern that Kona had been experiencing over the past 3 years, which was increased rainfall (approximately 94” per year), cooler daytime and nighttime temperatures, no dry season, and cloudy days. The shift has been to more of the “normal” weather pattern known to Kona, 6 months dry November-April and 6 months wet May-October. Actually, we have yet to see if the rainy season will be returning in April or May, as there are still many unknowns with the new variables of Climate Change. But the sun has returned, there is minimal rainfall and the grapes are much happier. Gerry thinks this summer may be a grand cru year, as many of the grapes are now old enough to taste for the first time, and the older vines should be producing more clusters. Grapes will start producing in the second or third year, but vines will take between six to eight years before you know the true value and taste of your grape. In the early years, it's best not to push the vine for maximum production as it will create a cycle of heavy production one year and then the next nothing. Photo below: A vine that has been pruned 95%.
Grape vines need yearly pruning. Pruning will give you more scions to plant out and/or share, and you maximize the number of grape clusters on the vines for the next summer. In past years, Gerry pruned at the end of February, which is the very end of the dormancy cycle. Remember that during the Fall of 2021 as the rained ceased and the weather became warmer and drier, the vines lost many of their leaves, which is part of the natural grape cycle, then the Chinese Beetles and Gerry helped remove the rest of the leaves and created a true dormancy period of rest for the grapes. In 2017, Gerry would prune back about 75% of the years growth (which could be 30 feet or more!) but by 2020 it became obvious that the vines needed to be pruned every year about 95%. By this summer and next summer we should be seeing that when the vines are 95% pruned back, they will produce more fruit on each of the 2 buds left on the multiple spurs, instead of the plant using all its energy to grow longer vines and leaves and less fruit.
This year Gerry began to see spring budding of one variety in late January 2022 which is the earliest we have seen in the past 6 years. Budding signals that Spring is coming and the vines need to be pruned Out of the 56 varieties we have trialed over the past 6 years, there are 14 very promising varieties we are now watching in the vineyards.
Photo: 13B first variety to bud and set grape clusters this year.
By the middle to end of February, all varieties were ready to be pruned. As of the first week of March, all vines have been pruned for this year. You can watch 2 new videos of Gerry pruning 2 different grapes so that you can see his pruning techniques. They are now up on our video page.
Having a good pair of hand pruners, like the Felco model is important and easier on your hands. You want a clean cut. Once a grape variety is pruned, Gerry has a variety of uses for the vines.
First, Gerry cuts scions from the older wood for planting in pots in the greenhouse. There are a few other ways to start a new grape that will be covered later. He looks for the best wood, not too thick or thin, with buds that are well spaced, not too close together or too far apart. He is looking for 4 buds on the scion. Two buds will be planted below the soil and the other two will become the vines. He cuts the scion about 8-9 inches in length, the bottom cut is flat, one quarter inch under the lowest bud, and the top cut is a 45 degree angle, an inch above the top bud. Next, he makes a moist, but not too wet, paper towel to wrap around the bottom of the scions as they will be placed in the fridge until he is ready to plant them out. Scions can stay in the fridge like this for up to one year. Photo below: Gerry making tags for the scions.
Be sure to label the scions to keep varieties separate, but don’t use tape as it degrades in the fridge. Gerry uses an aluminum tag, writes the variety name on the label with a marker, and uses copper electrical wire to bundle scions by variety. When he is ready to plant, he plants scions of one variety in three different places; directly in the soil of the vineyard (saving a years time), in one gallon pots in the greenhouse (one to two scions per pot) and in a "nursery" section of the garden that is protected, fertile and used just for starting scions. Sometimes when the scion will not root in the soil (because it was too cold or wet) then you have backups in other places, as not all scions will root. You may have other techniques for rooting woody cuttings that have been successful for you and you should try those. Photo below: Planting out scions from 2022 pruning.
Secondly, he cuts the rest of the pruned vine into pieces as kindling to start the morning fire in the fireplace during the winter. The ash from the fireplace is recycled and lightly sprinkled into the soil adding an amazing array of available minerals. Thus, the cycle is circular and sustainable.
This year, 2022, Spring has come very early, and as the grapes are pruned they are deeply watered and given some compost and kelp to awaken them and encourage growth now that the Spring forces are at work.
The next Blog will be about training the grape vines as they reemerge for this years growth as they need to be tied up to encourage them to grow in the directions you want.
Check out all 12 videos from this year, now up on our Kawanui Farm youtube channel and posted on our website video page.
We continue to post on Instagram many times per month, and encourage you to also post photos of your grape vines in Hawai’i with a short description. #grapesforhawaii
Our favorite Grapeman Lon Rombough Of Oregon, and author of The Grape Grower passed away a few years ago, but his family still maintains his website of excellent grape information. Check out their website
Lon also created a video called "Results of Proper Pruning of Grapes" that I'm sure you will enjoy. http://www.bunchgrapes.com/videos.html
We look forward to sharing more information with you in June 2022. By then we will have a good idea of fruit production for the Summer that will be processed into juice, dried raisins, and eating out of hand. Fingers crossed! As always let us know if you have any questions or comments at the bottom of the Blog page. Mahalo for your interest,
Gerry Herbert and Nancy Redfeather
Kawanui Farm - Kona, Hawai'i
Photo below by Shawn Linehan Photography