The Early Grape Harvest - July 2022

Interestingly enough, grape production worldwide is currently experiencing

great changes. As the weather heats up, grapes that had been grown for the the table and for wine over the past 10,000 years, especially in the Mediterranean countries, are experiencing huge declines in production. It has become too hot to produce Champagne in France and so England is picking it up. Here at Kawanui, our SARE Research and Education Project has been vetting table grape varieties for their hardiness and taste in the face of climate change since 2015.

This summer is the first time we have been able to evaluate grape production for some of the varieties that were planted from 2015-2020. Let’s look at the process for one of those grapes, Joseph Fennell’s “Tamiami" in the photo below. It’s parents are Shuttleworthi (a wild grape from the Everglades) and a Muscat called “Malaga” which is an ancient grape from Turkey or Syria.

This is exactly the type of grape I had been looking for. This variety can take both heat and rainfall, which is important for subtropical grape production. The process I will describe is the same one I have followed for all the varieties.

I started with a single Tamiami in 2015 that was set out in the first vineyard with the other varieties I had received from Ken Love. It grew well, and so the following year I made scions and started them in the nursery. The ones that looked the best, I set out in the vineyard and began observing them. Then from the most hardy of those, I again made scions grew them out, set them out, and observed their growth. Plants that were not hardy were pulled out. I did this 3 years in a row until today I have 4 acclimatized Tamiami in different vineyards that are producing a good amount of fruit. This year’s production from the oldest plants is a good indicator of the kind of production I should be seeing in the future. The four plants had 132 large clusters after thinning out at least 60 smaller ones. As of July 2022 these grapes are just beginning to turn black. (more to come)

For a Summer 2022 Tour of our 5 vineyards check out our new Video.

I also have been experimenting with how much I should cut back the grapes each February to encourage more flowering and less leaf growth. In the subtropics, grape varieties that are suited for this type of climate have a tendency to exuberant growth of the vines, sometimes as much as 30 feet in each direction. I started by pruning back 75% of the vine growth every Winter, but that wasn’t enough. So then the next year I pruned 90% and that was also too little. Last year I pruned 98% of the year’s growth of vines. The grape vines while still vigorous are somewhat shorter this year. Also, during the summer, I prune off any vines that touch the ground and occasionally thin out the vines to bring the sun into the inner area of the trellis. This also increases air flow. Grapes need to be vigorous to out compete the Chinese Beetle but not too vigorous to impede fruit production. I have observed that as the years go on, the grapes are less and less impacted by the Chinese Beetle. Perhaps they are adjusting chemical combinations in their leaf structure to repel the Beetles. Whatever the reason, the overall health of the vineyards is increasing as time goes on.

First Harvest Season - Summer 2022

For a Summer 2022 Tour of our 5 vineyards check out our new Video.

We are beginning the first bigger Harvest Season which will last from June to early fall. We have had small clusters in past years from a variety of grapes, but this year a few of the varieties are old enough to really begin to produce like Tamiami and 852.

We just harvested 36 clusters from Isabella, and pressed them into juice, but we did not like the taste. It has a thick skin that you can’t chew up easily, and a large seed, so it’s not an edible grape.

So we decided to use our first pressing to make some wine that did not have a pleasant flavor. But we have noticed that if the grapes are eaten when they are very dark purple and soft, they have a somewhat sweet flavor. We will give this grape another few years to mature and see what happens.

We were also able to taste the Meyer 6-7. This is a three year old Texas grape with a Florida introduction. The grape had only 6 small clusters, but enough to taste. It has a thin skin and small seed easy to chew. But the taste was sweet and sprightly and has shown us it’s unique potential here.

We also tasted the 13-B. It was very juicy, thin skin, tiny chewable seed, but not as sweet as we would like it. Since this grape is only three years old, we expect great possibilities in the future. We will have more discussion, photos, and videos of the harvest as the summer progresses.

Our newer varieties are only producing a few clusters as they are still young. It takes three years to see a single tiny cluster, and from six to eight years to realize production potential and taste in a variety. Like all agricultural projects this is a slow process but a most important one. Grapes are a superfood and as we are seeing, there are varieties

that can be grown in the subtropics for juice, wine, table, and raisins for Hawaii’s growers.

Stay Tuned as the Summer Progresses…there will be more to come and Mahalo for your continued interest.

Please post any grape photos you have on Instagram #grapesforhawaii and we will also!

Mahalo and Aloha,

Gerry Herbert

Kawanui Farm

www.kawanuifarm.org