Grafted Watermelon Production in Southcentral Alaska

View the project final report

Commodities

• Fruits: melons

Practices

• Crop Production: beekeeping, crop improvement and selection, grafting, high tunnels or hoop houses, pollination, pollinator habitat
• Education and Training: demonstration, display, farmer to farmer, on-farm/ranch research, workshop
• Pest Management: mulching - plastic

It is currently estimated that Alaska imports more than 95% of the $2 billion spent on food purchases each year. The effects and implications of enabling local food production are many and widespread. Currently, most imported food arrives via boat or plane. If our food supply is interrupted, it has been estimated that grocery stores at any one time have a maximum of two weeks worth of food stocked up. As food is being imported, the money paid for it is mostly taken out of state by large grocery chains. Money that is paid to producers within the state has a much greater effect on local economies and is circulated more than that paid to out-of-state companies. Alaska is very much a rural state and many communities are off the "road system". Meaning all of their food must be flown or boated in after it has been shipped to a central hub, like Anchorage. This drives prices for groceries sky-high in rural communities and nutritional foods are often not purchased because of these costs.

Nowhere in the world is the climate changing as rapidly as it is in the Arctic and Subarctic regions. Climate modifying structures, specifically high tunnel cultivation and/or soil warming techniques using solar energy-capturing materials, are enabling growers in these regions to produce fruits and vegetables that were once thought not possible. The USDA estimates it has awarded 4 million dollars in contracts and grants for high tunnels within the state of Alaska. High tunnel cultivation is becoming less of a novelty and more of an accepted regular practice in agriculture across the state.

This project proposes to research whether it is possible to enable outdoor and unheated high tunnel production of watermelon fruit production in south-central Alaska by grafting onto commercial rootstocks that have been proven in other studies to increase vigor, fruit size, storage duration, and other positive qualities. Open-pollinated and hybrid varieties of grafted and non-grafted watermelon plants will be evaluated for production feasibility, vigor, and fruit quality. Self-funded, baseline evaluations of grafted and non-grafted open-pollinated varieties have already been taking place in 2015 and 2016 here in Anchorage. Plants were grown outdoors using Infrared Transmitting Solar Mulch and indoors in an unheated high tunnel. These evaluations have been fruitful and we have begun to see some open-pollinated varieties and growing methods emerge that we believe warrant more investigation. Another component of the study is to work on pollination methods using native insects and honeybees. There appears to be a 3 to 4 week period in which pollination is crucial in order for fruit to mature before first frost. During this crucial period of first female flowering, there are many sources of food other than horticultural crops for native bumblebees and domesticated honeybees, and so pollinators might be lured away to other plants even though the watermelon are nearby. Mason bees are not recommended for outdoor use in Alaska due to low temperatures and so it is advantageous to explore utilizing the many native bumblebees. Hand pollination has been successful, but insect pollination is more desirable in most all production settings. Keeping honey bees is not always desirable for a grower in Alaska due to the presence and interest of black and brown bears. One of the objectives of this study is to utilize nests for native bees in the immediate vicinity of the crops. Nests for native bees will be both made and purchased and placed around the crops outside. Mason bee nests and cocoons will be purchased and placed inside the high tunnel.

The results of this research will be shared with the Alaskan agricultural community through lectures, classes, a website, and a fact sheet. These will include grafting methods, recommended pairings of rootstock and scion varieties, and a recommended production schedule. There are currently few, if any, growers in the state that plant watermelons for commercial production. Our farm, Flattop Farm, is the only business that we know of that has been offering locally-grown grafted watermelon plants to homeowners and growers within the state over the past two years. There is a perception that it is impossible to grow non-grafted watermelons outside and that in unheated high tunnels, results are not consistent and not always desirable. By publicizing our methods and results, we hope to educate and encourage homeowners and commercial growers to either graft their own plants or to try buying the young plants and grow them to fruition.

1. Evaluate performance of scion and rootstock combinations, building on the past two years as baseline studies. a) Graft take percentage and plants that make it to saleable quality will be logged in mid-late June of 2017 and 2018. b)Total fruit production of each scion/rootstock combination, including date of harvest, weight, and brix will be recorded and finished by mid-October in 2017 and 2018. Results will be compared to ungrafted controls.
2. Utilize native wood nesting, cavity nesting, and solitary bees for pollination of watermelon plants. Bee nests that are appropriate for each type will be purchased and placed around the crop. In addition, mason bees will be purchased and trialed and placed in housing that is specific to their needs. a) Nests will be placed by May 1, 2017, and a survey of the nests will be conducted weekly from June 1 2017/2018 through the end ofJuly 2017/2018. Number of occupied nest sites and visual activity will be logged during the survey.

3. Educate the public on the process and our results. a) Teach how to graft watermelon using the hole insertion technique and what some of our baseline results have shown so far at the Matsu Master Gardener's Conference April 22, 2017 b) Teach a class at Alaska Mill & Feed on grafting watermelon during the summer of 2017 and 2018 c) Teach a class at Alaska Botanical Garden's 2018 Conference.  d) Publish, at the minimum, a fact sheet showing our recommendations for growing grafted watermelon in southcentral Alaska by December 2018. e)  Use the media to notify the public of the study and it's potential benefits for Alaska by December 2018. This can include print, TV, and/or radio. f) Make contact with and set up time to teach a class to Kenai Peninsula growers in the early Spring of 2018. g) Present the project at the research plot of Alaska Botanical Garden during their Harvest festival in 2017 and 2018.
4. Survey growers and homeowners who have participated in the lecture and classes as to whether they will consider trying to adopt watermelon crops as something that they grow. Have the results of the surveys ready by December 2018.