Winter squash: extending the season and expanding the uses

Final report for OW16-008

Project Type: Professional + Producer
Funds awarded in 2016: $49,958.00
Projected End Date: 01/15/2019
Grant Recipient: Oregon State University
Region: Western
State: Oregon
Principal Investigator:
Oregon State University
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Project Information


Winter squash is a delicious and nutritious vegetable. PNW retail winter squash sales peak in October/November and decline to April. Butternut makes up 1/3 of sales, spaghetti squash 17%, acorn and delicata at 12% each, and a diversity of other types filling in the remaining 25%.  Regional wholesale squash farmers supply much of the organic winter squash in October and November but not thereafter, as farmers have not been successful in storing squash into the winter. Half of the winter squash sold in December, and almost all of it sold from January through April, is imported from California and Mexico. Consumers shopping in natural foods stores increasingly prefer local sources, so there is a local organic squash sales opportunity from December through April.  Project distributors/retailers sell more than 200,000 pounds of squash per month in October and November, with sales dropping 80% by April. If local farmers picked up an additional 25% of the December sales, plus 75% of sales in January-April, they would sell an additional 300,000 pounds (8500 35-pound boxes). If sales volume also increased 20% from December-April, they would sell another 1700 boxes. At approximately $25/box, farmers selling to these markets would collectively gross an additional $250,000 each winter. These farmers wholesale to other markets that would purchase more local squash if available.

Smaller farms are increasingly focusing on winter marketing through CSAs, farmers markets, and restaurants as demand for year-round local produce increases. These farmers struggle to grow crops for sale in January through March. They have trialed varieties and experimented with storage to extend the squash season with little success as they don’t have reliable variety and storage information.

Identifying high yielding varieties with excellent winter culinary quality that are reliably long storing under fluctuating farm conditions is a research priority for these two farmer groups.


Project Objectives:

Objective 1: Identify winter squash varieties that are profitable to grow and store for marketing from December to March in western Oregon

Objective 2: Describe taste (flavor and texture), marketing window (when they taste best) and best culinary uses (recipes) for varieties in Objective 1.

Objective 3: Develop marketing materials for varieties identified in Objectives 1 and 2. See Outreach Materials section below.

Objective 4: Engage farmers (and distributors, retailers) with results of Objectives 1-3 and other information on squash varieties, production, storage, sensory quality, and culinary uses. 



Materials and methods:

Objective 1: Identify winter squash varieties that are profitable to grow and store for marketing from December to March in western Oregon

Growing season 2016 and 2017: Winter squash varieties that in preliminary trials yielded well in western Oregon and stored well under fluctuating barn conditions were formally evaluated in both on-farm randomized trials (3 reps) and research station replicated experiments (irrigated and dryland). Squash were harvested when physiologically ready and total yield, average fruit weight, and range of fruit weight were quantified. Subsamples of squash from all experiments  were stored in both a closed barn bay (maintained above 40F) and a walk-in cooler maintained at 55F and 60% RH. Squash was evaluated for percent rotten and quality (dry matter, Brix) from harvest through March. Farmers also grew and evaluated varieties informally on their farms.

Varieties grown in all experiments:

Kabocha family (C. maxima): Sweet Mama (green F1 AAS winner), Winter Sweet (gray F1), Blue Kuri (gray OP), Shokichi Shiro (mini gray F1) kabochas; Crown (gray heirloom OP); Silver Bell (gray to pink heirloom OP); Red Kuri (red OP); Gold Nugget (orange OP, AAS winner); Georgia Candy Roaster (pink heirloom OP); Sibley (blue heirloom OP). Acorn family (C. pepo): Gill’s Golden Pippin acorn (Oregon heirloom orange OP), Zeppelin delicata (Oregon-selected OP), Small Wonder spaghetti (F1). Butternut family (C. moschata): Betternut butternut (F1), JWS 6823 butternut (F1), Early Remix butternut (Oregon-selected OP), Black Futsu (Japanese heirloom OP); C. maxima x C. moschata cross: Tetsukabuto (F1).  OP = open pollinated, less expensive seed, seed can be saved; F1 = hybrid, more expensive seed, seed cannot be saved.

Objective 2: Describe taste (flavor and texture), marketing window (when they taste best) and best culinary uses (recipes) for varieties in Objective 1. Fall/winter 2016-2017: Fruit were evaluated for quality through out storage and the project chef, Timothy Wastell (as well as other chefs) worked with the squash to develop recipes. Squash culinary information and recipes are available at

Research results and discussion:

The project grew many squash varieties in 4 trials and stored them in two storage environments; there is too much data to report it here. Results from 2016 and 2017 are summarized in Jennifer Wetzel's thesis "Winter Squash: Production and Storage of a Late Winter Local Food" at and one paper was submitted to HortSciencein 2018 (with another one to be submitted in 2019).  Sixteen varieties of squash, including varieties from Cucurbita maxima, C. moschata, C. pepo and one C. maxima x C. moschata interspecific hybrid ‘Tetsukabuto’ were grown in three split-plot field trials, with irrigation as the main plot and variety as the subplot. Two irrigation regimes, full irrigation and zero irrigation, were assessed for their impact on yield and storage losses. Yield was calculated for each variety at harvest, and all of the varieties were stored in a barn bay environment with fluctuating temperature (always above freezing) and fluctuating relative humidity (RH). A subset of the varieties (seven of the C. maxima types and the interspecific hybrid ‘Tetsukabuto’) were stored in two different storage environments: 1) barn bay conditions, and 2) controlled environment storage (10.0 to 12.8 oC, 50% RH). The subset of varieties stored in two different environments performed best in the barn bay environment, which is contrary to extension service publication recommendations that advise storing winter squash in a controlled environment between 7.2 and 12.8 oC and RH between 50 and 70%. Several varieties were found to be both long storing and rot resistant, including the interspecific hybrid ‘Tetsukabuto’, and the C. maxima types ‘Winter Sweet’ and ‘Crown’. Zero irrigation (dryland farming) significantly reduced the incidence of storage losses due to rot; however, the reduced rate of loss must be taken into consideration with the reduced initial yield at harvest under dryland conditions. In January, the average percent loss in storage was applied to the average yield at harvest to determine the relative yield after four months of storage. Under barn bay conditions, the highest relative yielding varieties under irrigation were ‘Tetsukabuto’ (45.1 tŸha-1), ‘Small Wonder’ (37.1 tŸha-1), and ‘Winter Sweet’ (30.0 tŸha-1); for dryland production, the top performers were ‘Small Wonder’ (45.4 tŸha-1), ‘North Georgia Candy Roaster’ (26.7 tŸha-1), and ‘Silver Bell’ (24.3 tŸha-1). . 

Participation Summary
8 Producers participating in research

Research Outcomes

2 Grants received that built upon this project
3 New working collaborations

Education and Outreach

15 Consultations
2 Journal articles
4 On-farm demonstrations
3 Webinars / talks / presentations
5 Workshop field days
2 Other educational activities: Website: Two Squash sagras (festivals).

Participation Summary:

100 Farmers participated
7 Ag professionals participated
Education and outreach methods and analyses:

In January/February of 2017 and 2018 the project hosted a winter workshop in which we discussed project finding and in 2017 and 2018 planned next steps with cooperating farmers, seed companies, and NGOs. The project partnered with farmer cooperators on 5 on-farm variety trials. Two field days were held in August 2017 and again in 2018 in partnership with the Dry Farming Collaborative. In December 2017, the project launched its consumer-facing website,  In addition, the project partnered with Friends of Family Farmers in Dec 2018 and Dec 2018 in the coordination of Squash Sagras in Portland, OR in combination with a Fill Your Pantry event. Eight chefs offered samples of 8 different and novel squash recipes, chef Tim Wastell demonstrated best squash butchery techniques, and visitors cuddled squash in a squash photo booth. Farmers sold a lot of squash!

35 Farmers intend/plan to change their practice(s)
23 Farmers changed or adopted a practice
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.