Progress report for WPDP25-003
Project Information
The proposed project will create educational resources on sweetpotato production for agriculture professionals in the Pacific Northwest (PNW) and standard research protocols for researchers in the Pacific Islands.
Farmers and gardeners in the PNW have expressed interest in growing sweetpotatoes but have found information from the internet to be misleading or flawed. Sweetpotatoes are a viable new storage crop that can provide a source of income for farmers throughout the year in the PNW, but production information is from the Southern United States, which has different environment conditions. PNW Extension educators lack complete region-appropriate resources to educate growers on the production and storage requirements to make sweetpotatoes a profitable and productive crop.
Researchers within the Pacific Islands have requested assistance with creating standard protocols that would allow data from sweetpotato experiments to be compared as they work to optimize sweetpotato production throughout the Pacific Island region.
A series of educational videos on sweetpotato production practices including slip production, planting techniques, input requirements, harvest timing, curing, and storage will be produced and dispersed to agricultural educators throughout the PNW and uploaded on WSU Extension websites for public viewing. An existing PNW growing guide will be updated to reflect farmer feedback and recent research. Factsheets and videos demonstrating standard research protocols and methods will be created and shared with colleagues researching sweetpotatoes in the Pacific Islands.
Videos will be filmed with cell phone technology using an informal presentation style, to be more relatable to farmers and gardeners. Extension educators and volunteers, farmers and researchers will provide feedback for revision and additions to the guides and new factsheets and videos as applicable.
- Increase quality, relevance, accuracy, and usefulness of information on growing sweetpotatoes in the Pacific region available to Extension professionals and Master Gardener Volunteer community educators.
- Provide Extension professionals and Master Gardener volunteers with resources to teach farmers and home gardeners how to grow sweetpotatoes.
- Increase farmers’ knowledge of how to grow sweetpotatoes in the Pacific region, including slip production and planting, variety selection, crop management, integrated pest management, harvest, curing and on-farm storage.
- Promote farmer-to-farmer education of sweetpotato growing practices.
- Provide protocols to researchers for standardized methods for sweetpotato field trials.
Sweetpotato (Ipomoea batatas) is a productive, nutritious, and climate-resilient crop that thrives in a wide range of growing conditions. Sweetpotato production in the US is concentrated in North Carolina, California, and Mississippi (USDA NASS, 2022). Yet studies in Pennsylvania, New Hampshire, and northwest Washington have demonstrated yields equal to or higher than the national average when sweetpotatoes are grown with soil-warming plastic mulch (Duque 2020, Duque et al. 2022, Shrestha and Miles 2022, Sideman 2015). Educational resources produced in southern states have limited applicability for growers in the Pacific Northwest (PNW) and the Pacific Islands (hereafter jointly referred to as the Pacific region). For example, in southern states sweetpotato slips are produced outdoors in early spring, while in the PNW, slips are produced indoors due to the shorter growing season, and in the Pacific Islands, sweetpotatoes are replanted within a few days of harvest for continuous production. Many farms in the Pacific region are small, mixed-vegetable operations where planting, field management and harvest are done by hand rather than with large-scale equipment as in the southern United States, which affects growing practice recommendations.
Regionally appropriate educational resources are needed for producing sweetpotatoes in the Pacific PNW. Twenty-five farmers and gardeners attended a sweetpotato field day each year at WSU Northwest Research and Extension Center in 2023 and 2024, and 14 farmers in 2023 and 32 farmers in 2024 participated in on-farm trials. The barriers to successful sweetpotato production in the PNW are a lack of knowledge about slip production, soil-warming mulch, weed control, and post-harvest curing. Extension educators, including WSU Master Gardener volunteers who work with urban immigrant communities that are trying to grow familiar foods in an unfamiliar climate, do not currently have the information resources needed to support interested farmers and gardeners on successful sweetpotato production. This project will develop videos and update fact sheets to create a PNW- specific set of resources to support Extension education and outreach about sweetpotatoes.
In the Pacific islands, several researchers are investigating sweetpotato production to boost local food systems. There is a need to develop standard research protocols for sweetpotatoes so results can be compared. For example, researchers will benefit from standard protocols for consistency in rating plant growth, pest damage/tolerance, weed competitiveness, and yield based on USDA size categories. This project will develop factsheets and videos to create standard research protocols and methods that will be shared with colleagues studying sweetpotatoes throughout the Pacific region.
A professional development grant focusing on sweetpotato resources for Extension programs has not yet been funded for the Western region. In the WSARE PDP project EW97-003, eight educational videos highlighting general sustainable agriculture practices were developed for Hawaii, Guam and the Northern Mariana Islands. The major outcomes from the project were: Extension agents were trained in sustainable agriculture principles using the videos; the videos extended the project’s outreach throughout the Pacific region; a close-knit group of agents in the Pacific Islands was formed; and future Extension education projects to develop short training videos were recommended.
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Summer 2025 |
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Winter 2025 |
Spring 2026 |
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Spring 2027 |
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Slip production and planting trials |
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Take photos for growing guide |
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Film videos for growing and research protocol series |
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Curing trials |
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Write growing guide and research protocols |
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Edit and produce video series |
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Draft of growing guide and videos provided to educators. Collect and evaluate feedback |
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Research protocols provided to researchers |
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Collect longitudinal data on growing guide, videos and research protocol use |
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Publish final growing guide and protocol factsheets |
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Publish final video series |
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Cooperators
- (Researcher)
- - Producer
Education
This project created and/or updated written and video resources to educate about sweetpotato production in the Pacific Northwest and support research efforts in the Pacific Region. Resources including a comprehensive sweetpotato growing guide, short instructional videos, and written research protocols were created to be used by agricultural educators, farmers, gardeners and researchers. Workshops were offered to teach researchers the new research protocols.
Education & Outreach Initiatives
Provide Extension professionals and Master Gardener volunteers with resources to teach farmers and home gardeners how to grow sweetpotatoes.
Sweetpotato growing guides on 6 different topics (varieties, slip production, production practices, pests and diseases, greens, curing and storage), originally created as part of SARE project number SW23951 on-farm research trials, were sent out to agricultural educators throughout Washington State and western Oregon in January 2026 for review. We targeted Extension Educators working with small farms in western Washington and western Oregon and Extension Master Gardener volunteers who provide education to home gardeners and homesteaders. Evaluation requests were sent directly to Extension Educators working with small farms in western Washington (17) and western Oregon (4). In addition, list serves targeting agricultural educators included WSU Extension Master Gardeners (3,500 community horticulture educators), and the WSU Food Systems Program (subscribers unknown at time of reporting). Potential reviewers were asked to review the growing guides and provide feedback using a standard survey SP growing guides_western SARE eval form .
Two short videos on sweetpotato topics were completed (How to Mail Sweetpotato Slips and How to Build Sweetpotato Beds with Recycled Plastic), and will be sent out along with two videos created as a part of SARE project number SW23951 (How to Produce Sweetpotato Slips Indoors and How to Plant Sweetpotato Slips) for evaluation by agricultural educators in February of 2026 using a similar evaluation form as used for the growing guides, and using the same outreach audiences.
Sending these resources out for review by agricultural educators had a twofold purpose. First, we wanted feedback from end-users to make sure that the resources being created were useful to the intended audience. The second purpose was to alert educators to the availability of resources for them to use when working with their constituents, and to the fact that there is increasing interest among farmers and gardeners in growing this crop in the Pacific Region.
Complete footage has been recorded for additional videos including Handling Mailed Slips, Sweetpotato Bed Setup at the WSU Northwest Research and Extension Center, How to Pre-root Slips, Harvesting with a Potato Digger and Harvesting with a Mulch Lifter. These videos are in the editing process. In 2026 footage will be obtained for creating additional videos included in the project proposal.
Survey results will be reported in 2027.
Increase farmers’ knowledge of how to grow sweetpotatoes in the Pacific region, including slip production and planting, variety selection, crop management, integrated pest management, harvest, curing and on-farm storage.
Sweetpotato growing guides on 6 different topics (varieties, slip production, production practices, pests and diseases, greens, curing and storage), originally created as part of SARE project number SW23951 on-farm research trials, were sent out to farmers, gardeners and homesteaders throughout Washington State in January 2026 for review. We accessed appropriate audiences by sending the evaluation request out via email list serves intended for farming and gardening audiences. List serves included Skagit Growers (6,000 emails), WSU Regional Small Farms Program (1,300 emails), The Washington State University Extension Master Gardeners (3,500 emails), and asked farmers and gardeners who have expressed interest in growing sweetpotatos to give feedback in return for receiving sweetpotato slips in the spring of 2026 (95). Potential reviewers were asked to review the growing guides and provide feedback using a standard survey SP growing guides_western SARE eval form .
Two short videos on sweetpotato topics were completed (How to Mail Sweetpotato Slips and How to Build Sweetpotato Beds with Recycled Plastic), and will be sent out along with two videos created as a part of SARE project number SW23951 (How to Produce Sweetpotato Slips Indoors and How to Plant Sweetpotato Slips) for evaluation by farmers, gardeners and homesteaders in February of 2026 using a similar evaluation form as used for the growing guides, and using the same audiences.
By involving growers in the process of creating resources, we can ensure that the resources are appropriate for the growers in western Washington, and alert growers to the existence of growing guides and videos that will help them be successful with a new crop.
Survey results will be reported in 2027.
Promote farmer-to-farmer education of sweetpotato growing practices.
In addition to seeking grower feedback on sweetpotato growing guides and short videos, we filmed diverse production practices on farms. Farmers directly participated in the creation of footage for the following videos in 2025: How to Build Sweetpotato Beds with Recycled Plastic (Wild Edge Farm), How to Pre-root Slips (Sunbaked Greenhouse) and Harvesting with a Potato Digger and Harvesting with a Mulch Lifter (Hedlin Family Farm). In 2026 additional filming will take place on farms for videos on topics including curing and storing roots, feeding vines to livestock, alternative planting methods, harvesting by hand and others.
Create and provide protocols to researchers for standardized methods for sweetpotato field trials.
Five protocol guides were created to support Pacific Region researchers conducting sweetpotato variety trials. Research protocols have been submitted as products of this grant, and include:
- Sweetpotato: Measuring the Longest Vine
- Sweetpotato: Measuring Canopy Cover with ImageJ
- Sweetpotato: Measuring Root Yield
- Sweetpotato: Measuring Brix Using an Electronic Refractometer
- Sweetpotato: Measuring Root Damage with the Wireworm-Diabrotica-Sestena (WDS) Severity Index
These protocols were provided to colleagues studying sweetpotato production in the Pacific Islands. Five workshops (one for each protocol) were held in January 2026 at the College of Micronesia on the island of Yap, Federated States of Micronesia (FSM) to demonstrate and allow participants to practice research protocols, and to receive feedback on the protocols.
As a result of feedback from workshop participants, the research protocol, Measuring Canopy Cover with ImageJ, was updated with information on using ImageJ on bare soil, as opposed to on plastic mulch. Sweetpotatoes are typically grown using plastic mulch in western Washington and grown on bare soil in the Pacific Islands.
10 Extension Agents, Extension Assistants, technicians, field assistants and PhD students from the College of Micronesia participated in the workshops.
Additionally, footage for short instructional videos has been recorded for Measuring Longest Vine and Measuring Canopy Cover with ImageJ research protocols. These videos are currently in the editing process, and footage for Measuring Brix Using an Electronic Refractometer, Measuring Root Damage with the Wireworm-Diabrotica-Sestena (WDS) Severity Index and Measuring Root Yield will be completed in 2026.
Educational & Outreach Activities
Participation summary:
Learning Outcomes
Project Outcomes
Will be reported in 2027