Growing Table Grape Varieties for Subtropical Hawaii Using Organic Practices

Progress report for FW21-378

Project Type: Farmer/Rancher
Funds awarded in 2021: $25,000.00
Projected End Date: 04/01/2023
Host Institution Award ID: G324-21-W8613
Grant Recipient: Kawanui Farm
Region: Western
State: Hawaii
Principal Investigator:
Gerry Herbert
Kawanui Farm
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Project Information


Although there have been many past attempts to grow table grapes in Hawaii, locally grown grapes are not commonly available for sale, nor are plants or the grower information necessary for growing grapes in the subtropics. There is great potential to find varieties that can be successfully grown by market growers and home producers adding a new nutritional food for Hawaii’s people, creating new growing information and a repository for grape scions, and developing an import substitution that will help diversify Hawaii’s agricultural base.

Question:  Can this project find the right grape varieties that will successfully grow and thrive in the subtropics consistently producing delicious table grapes using organic practices? 

Using a unique research model, that includes extensive investigation into the work of T.V. Munson, Joseph L. Fennel, Lon Rombough, and Francisco Wallington-Linares, the project will choose 35 varieties available on the USDA GRIN Grape Repository at UC Davis that were successfully bred in semi-tropical and subtropical regions, have wild grape genetics in their parent lines and have proven potential in Southern Texas, Florida, Puerto Rico and the Caribbean.  Using that information, and building upon the work of Ken Love and “Grapes for Tropical Hawaii,” this project will vet these varieties at Kawanui Farm in Kona, Hawaii.

 In 2021, we reached out to grower groups across the State (List in Other Documents) and created a stakeholder group of 110 growers from all Islands that were interested in following our bunch grape research and education project.  Their location and emails are now in our WIX website list serve system.   Then, instead of 3 times per year, we created and sent our stakeholder group a quarterly Seasonal Blog that shared pertinent research information, identified new bunch grape Readings & Resources, and created and shared 10 on-farm videos on various grape subjects of interest.   These educational materials were also posted on our farm website each quarter.  Every week,  we continue writing our booklet “Growing Table Grapes in Subtropical Hawaii Using Organic Methods,” that we will be printing, sending out to interested Stakeholders,  and posting on our farm website in March 2023.  We continue to post current photos of grape varieties and practices etc. a few times a month on Instagram #grapesforhawaii.   At the end of this first year, that saw rainfall increase from 40 to 92" per year (for the past 3 years) we continue to work on creating a repository of successful bunch grape varieties that will continue to be vetted. A limited number of scions of successful varieties will be made available to stakeholders March 2023.  We are ending the first year of our SARE research and education project with 14 very promising varieties out of 56 we have vetted since 2015.  This year 2021-22 our weather pattern has returned to the more familiar wet/dry season, which should greatly increase fruit production that we will taste this summer, many varieties for the first time! All Blogs, photos, videos, and resource documents are available on  

Only Educational Objective Three has been modified.  There are  

Project Objectives:

Grape Survivors 2015-2022 Rainfall Chart Kawanui Farm 2003RESEARCH Objectives:

Project site:  Kawanui Farm is located at the 1,450 foot elevation on the western side of the Hualalai Volcano in the Kona District of Hawaii Island. The soil composition is rich basalt volcanic ash and the average rainfall is 42 inches but we have measured a low of 23 inches in 2003 and high of 123 inches in 2004.  2020 is looking like rainfall totals will be more than 100 inches. The farm faces southwest and the land is gently sloping. The vineyards use the modified Geneva Curtain style of grape trellis that has been sustainably built using old growth redwood from recycled water tanks. To my knowledge we are the first modern age people to live on this land, so the soils have always been used organically. 

Objective One:  Observe and record information for each of the fifty six grape varieties that have been vetted in the five vineyards.  (Observation Criteria in" Other Documents") Research findings year 1:  Gerry has over 100 pages of observations and notes from 2015-2022 following the Observation Criteria in Other Documents.  A summary of that information will be included here in attached documents.  A representative selection of notes and photos will be made into documents that will be included in this report.  See Log Book and Red Folder Summary and Photos documents (attached) 

Objective Two:  Research, observe, and document how best to prune and train each grape variety at the right time, with the right technique, the right amount of pruning, and create a dormancy period.  Research findings year 1:  The needed dormancy period for grapes was helped by a return to dry weather and cold nights.  All the leaves that had not already fallen were removed by hand by the end of December.   Right now (February 2022) Gerry is pruning all the vineyards and observing and documenting pruning by variety.  Two varieties began to bud out very early, at the end of January, and so they were pruned much earlier than we have ever pruned before, but each variety is different.  By the end of February all the grapes will be pruned and any scions will be planted out in the greenhouse.   Summary of observations will be included in this report.  (see Red Folder document and Blog #4 www/ for additional information on pruning)

Objective Three:  Experiment with, observe, and document sustainable organic growing methods that will achieve optimum growth, plant health, and eventually excellent taste. No outside inputs will be used, instead on-farm nutrients will be recycled creating compost and mulching systems.  Research findings year 1:  We applied compost, bone meal/shells, wood ash, kelp, when the vines when needed during their growing season, not during their dormant period.  Now that spring has begun in the subtropics (this year it was the end of January 2021) we are watering and applying compost and kelp to awaken them, as they had been dry for three months.  We have kept a thick layer of mulch on the surface of all the vineyards to protect the soil and preserve moisture as the late fall and winter this year has been very sunny and dry with 1/2 to 1 inch of rain per month.  All varieties are given the same treatment, varieties that did not grow well in 2021 were removed and more promising varieties were planted in those spots.  Just because a variety did not do well here, is not a reflection on organic practices.  Low input sustainable systems are essential for future food production in Hawaii.  The 14 varieties that have survived and thrived indicate that some varieties of table grapes can be successfully grown in Hawaii, however we have not tasted all the varieties, hopefully that will happen this summer.  Taste will be the final component.  

Objective Four:  Observe and record the effects of climate change on the grape varieties chosen for the vineyards. Research findings year 1:  There had been 3 years of constant rain (90+") during 2019, 2020, and 2021 in an area that "traditionally" has a 6 month wet 6 month dry season.  Also, the temperature  was well below normal, days and nights quite cool, and days cloudy.  The grapes all still grew, but some of the varieties died, the Chinese Beetles decimated others, and so this 3 year period was an extreme vetting process.  Of the 56 varieties 14 remain healthy and promising after 6 years.   The weather has returned to it's normal wet/dry cycle in late 2021.  The winter nights have been cool down to 56 degrees.  Soils in Kona are very porous with good drainage, but the 3 years of rain depleted minerals even with a layer of mulch on the surface of the soil the soil has become a bit harder.  Because our volcanic ash soils have been organically managed for 24 years, Gerry knows they will come back from any loss of nutrients in 2019-2021.  We continue to apply additional farm grown compost, but it's important not to provide too much nutrition, as we don't the plants to be all leaf and vine.  Grapes are grown traditionally in drier hotter areas, and so many of them are right at home.  With these changes in climate we had poor fruit production last summer, and the grapes that did fruit had diminished taste.  Even with subtropical parent lines, many grape varieties cannot grow and produce well with constant rainfall, but luckily, there are very few areas of Hawai'i that have a 12 month rainy season.  Part of the vetting process, in today's climatic rollercoaster, will be to observe and find varieties that will weather these extremes and thrive.  

Objective Five:  Taste and record the flavor profile of every grape variety.  Grapes produced in these systems must have excellent taste.  Research Findings year 1: Due to extreme rainfall and many varieties still young (including all he 2020 UC Davis scions), there was poor grape production last summer and we were unable to taste many of the varieties.  Of those we did taste, none of them were very sweet and the number of clusters was greatly diminished.  We expect all this to change in this summer's fruiting, as the weather has been dry and hot, exactly what grapes like.  


Educational Objectives: 

Objective One:

Identify group of potential stakeholders statewide interested in learning to grow grapes.  Education year 1:  After reaching out to a list of grower organizations, a grower group of 110 stakeholders was identified statewide who are interested in learning to grow grapes.  All names are now part of our WIX website list serve.  This makes communication with the group easy when we send out our Shout-out and Blog, containing research information,  resource additions to the website, and new photos and videos.  We are pleased that so many people were interested.  

Objective Two: Communicate ongoing research and educational information to stakeholder group that was identified in Objective One, in a short readable blog every four months for two years.  ( 6 blogs over 2 years) Education year 1:  By the end of March 2022, we will have posted 4 Blogs with interesting grape research information, links to new videos, photos, and resources. All Blogs are posted on  

Objective Three: Host an on-farm or virtual Demonstration/Workshop for stakeholders in August 2021. Education year 1:  Due to COVID, Objective Three has been modified and approved.  Instead of one in-person workshop in year 1,  we created 12 short videos each one illustrating an aspect that would have been covered in the workshop.  All videos have been posted on our farm website on our youtube channel.  

Gerry has also hosted 2 "mini-workshops" here for a morning with a few interested stakeholders who live in our area of Hawaii island.  They received a farm tour, and talk story with Gerry about his research documents and findings.  We keep in contact with many of our stakeholders by email as they ask questions and make comments.  We have a mini-group that have had Vineyards in California and now live in Hawaii.  We have 4 stakeholders in the Kona area and one on Oahu that we are sharing scions with in March 2022.  

Objective Four:  Host a second on-farm or virtual Demonstration/Workshop for stakeholders August 2022.  This Objective is for next summer.  We will need to evaluate where we are then with COVID.  Either we will make 10 more videos or have an in-person workshop.  In lieu of a Survey that would be given to workshop participants I thought of another way to fulfill that requirement.  IF we cannot have an in-person workshop in August 2022, we plan on reaching out to a group of 20 Stakeholders with the SARE Survey and ask them a few questions about our educational materials, were they effective, relevant, helpful, interesting, and compile the results.  I will submit the questions to SARE for approval.  

Objective Five: Write, publish, and mail a booklet “Growing Table Grapes in Subtropical Hawaii Using Organic Practices." Downloadable copy available on Kawanui Farm website.  Education year 1:  Once a week Gerry and I and sit down and write for a morning. We started writing the booklet last summer and we have written the Introduction and are on Chapter 6.  I have also been meeting with printers, because we would like this printed locally if possible, it will be a Spiral Bound plastic coated cover, with room for field notes at the back.  I think we are making good progress.  I would like to be finished by early next fall.  We need to wait until this coming summer of 2022 to actually taste many of the varieties that were planted years ago, and write up those chapters.   We bought our grape press and we are set to make juice, raisins, evaluate taste, etc.  

Objective Six: Create a grape repository of successful varieties for Hawaii's growers. Education year 1:  We continue to vet varieties, and whittle down the weaker ones, and we are making scions available to a few stakeholders in our area this year 2022.  It is still our vision to offer scions of our best varieties ( there will be limited supply) to Stakeholders who are really interested in March 2023 along with our published booklet either mailed or downloadable on our farm website.   



Click linked name(s) to expand/collapse or show everyone's info
  • Ken Love - Technical Advisor
  • Nancy Redfeather (Educator)


Materials and methods:


Research Plan and Objectives 2021-2023

Objective One:  Observe and record information for each variety added to the four vineyards. 

Record observations in logs daily looking for varieties that will thrive in Hawaii. By “thrive” I mean they are tough and hardy, resistant to Hawaii’s pests and diseases, can withstand El Nino drought cycles and years of extreme rain like 2020, three months of volcanic eruptions, can grow well in organic systems with no outside inputs, and have an excellent taste profile. Detailed Observation Criteria attached in More Documents.

Fourteen new table grape varieties from the UC Davis Grape Repository were added to the vineyards in April 2020 and were specifically chosen from extensive research into the complex parent lines that had been bred by well known American breeders. (see Citations) Each variety had been successfully grown in semi-tropical and subtropical regions of Southern Florida, Southern Texas, the Caribbean, and Puerto Rico, and had wild grape genetics in their parent lines. These genetics create an “introduction” into this subtropical region. This research approach is new, unique, and I believe will produce lasting results. 

End of Year One:  Please see attached documents Grape Log & Red Folder Research, Grape Log Photos, and Red Folder Photos, Rainfall Chart, and Vineyard Winners!

Objective Two:  Research, observe, and document how best to prune and train each grape variety at the right time, with the right technique, the right amount of pruning, and create a dormancy period.

Some grapes produce best with “long-arm” pruning, some like “short-arm,” and some do best with spur pruning techniques. Grapes will be pruned once a year, and since we never have a frost, we will need to put them into a leafless period of dormancy from December to mid-February each year to achieve the best grape growth in the following year.   Pruning will be done in the mid-February. I will continue to experiment with pruning different amounts from all vines to arrive at the best % to be pruned from each variety. I will also record all training techniques for each variety in my uniquely modified Geneva Double Curtain system.  See More Documents for details and photos of the “Modified Geneva Double Curtain System.

End of Year One:  Please see Grape Blog March 2022, and 2 Pruning Videos March 2022.

Objective Three:  Experiment with, observe, and document sustainable organic growing methods that will achieve optimum growth, plant health, and eventually excellent taste. No outside inputs will be used, instead on-farm nutrients will be recycled creating compost and mulch systems. 

For the past 50 years, I have been experimenting with organic growing methods first on my twenty acre farm in Mendocino County, California and later on my current farm in Kona, Hawaii. I graduated from UC Davis with a Science degree in International Agriculture Development (IAD) and had two majors in soil science and viticulture. I also worked at the Fetzer Winery for many years assessing brix levels for grapes during the crush and kept records on all fermenting tanks for the season. I have done extensive reading and application of organic methods both in temperate, Mediterranean,  and semi-tropical climates. I have been using organic methods of growing in my orchard and vegetable plots both in Mendocino and Hawaii. These organic systems will provide  essential plant nutrients and encourage deep rooting that will allow the grape varieties to withstand the climate changes that are already upon us. 

 On-farm nutrient recycling systems will include:

  1. Compost will be created using both nitrogen and carbon materials gathered from all areas of the farm. Using only on-farm inputs offers the best protection from the Little Fire Ant.
  2. Mulch will be created from organic farm materials recycled to preserve moisture and protect the soil from pounding rains and sun, creating a rich healthy system that feeds soil microorganisms and worm populations.
  3. On-farm wood is recycled through the home fireplace to make wood ash, an excellent addition to the soil.
  4. Bones from wild chickens, pigs, etc. will be processed through the fireplace and ground to create bone meal. 
  5. End of Year One:  Due to 3 years of rainfall we also began adding a soluble Kelp solution at the beginning of Spring 2022 to help replace micronutrients in the soil.  

Objective Four:  Observe and record the effects of climate change on grape varieties chosen for the vineyards. 

 Climate change is beginning to impact agricultural systems in Hawaii and it's effects will continue to unfold.  We will prepare for this uncertain future by planting varieties that will survive in changing environments using sustainable growing methods. I have chosen grape varieties that have the potential to perform in different extreme environments  such as deserts, mountains, swamps and river valleys. I will observe and record the effects of weather on each variety including drier periods, wetter periods, effects of volcanic activity, and new and different pests and diseases connected to weather for each variety. End of Year One:  See attached document Rainfall Chart, and Log Book & Red Notebook Research pdf., Grape Log Photos pdf., and Red Folder Photos pdf. 

Objective Five:  Taste and record the flavor profile of each grape variety.  Grapes produced in these systems must have excellent taste. 

Grapes will begin producing fruit in the third year, but to truly understand the taste prolife of each variety grown in different climatic years it will take a longer period of time.  However, most varieties that were planted will be producing fruit that will be tasted and used in a variety of value added ways from 2021-2023. It’s possible that some of these varieties will not produce flavorful grapes in this environment. It’s also possible that taste changes as climate changes. A year of extreme rains could produce a more “watered down” flavor and the next year with a drier climate could produce a grape with a more condensed flavor. A fine tasting grape is one that has a distinctive flavor, sweetness with an acid balance, an edible skin so it can be eaten whole, and if the variety has seeds they are softer and chewable.  I will create a chart that will reflect these qualities for each variety over the grant period and on into the future.  I will taste each variety out of hand, make them into juice, dry them for raisins, freeze them (sometimes creates a better taste), make jam and fruit leathers.   End of Year One:  We were not able to taste many varieties last summer due to rainfall, cloudy and cool conditions for most of 2021.  However, the weather pattern has changed and we had an early spring (end of January 2022) vineyards were pruned early as there was an early budding, and so we are anticipating good fruit set and harvest for end of Summer 2022.  

Participation Summary

Research Outcomes

110 New working collaborations

Education and Outreach

4 Other educational activities: Quarterly Blog sharing research and best practices, new vineyard photos, new grape resources, and 12 on-farm videos uploaded to our farm website as they occur.

Participation Summary:

Education and outreach methods and analyses:

All educational and outreach activities are describe in Educational Objectives.  Quarterly Blog, New Vineyard Photos, Instagram, new Resources added to Resource Page, on-farm videos of research and practices uploaded monthly.  I will be writing an article for the University of Hawaii CTAHR newsletter Hanai 'Ai describing our research as many UH folks are stakeholders.  Also, wanting to write an article for Edible Hawaiian Islands.  We have been asked by the Farmers Union to talk at an upcoming conference so we'll see if that is possible.  

Education and Outreach Outcomes

10 Producers reported gaining knowledge, attitude, skills and/or awareness as a result of the project

Information Products

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.