Final report for OW23-385
Project Information
By conducting participatory research on shade cloth in seed production and disseminating the results, this project will reduce risk for seed producers, improving their quality of life, as well as increasing the reliability of the supply of regionally adapted seed.
The quality, quantity and diversity of seed varieties available to producers impact their economic success, and their ability to farm in an environmentally sound manner. Increasing the number of successful seed producers contributes to the economic viability, environmental soundness, and social responsibility of our agricultural system. However, seed production is risky, especially in the face of increasing climate extremes. The Western states are an important region for the production of high quality vegetable seed, including tomatoes. These same states have been among the most impacted by increasing temperatures.
Based on surveys, interviews and focus groups, shade cloth was identified as the heat management option producers were most interested in researching, and tomatoes were identified as the crop for which Western seed producers have felt the most impact from extreme temperatures during pollination.
This project will conduct on-farm shade cloth tomato seed trials in WA, HI, and AZ, collecting plant, seed and climate data at all sites. A Partial Budget Analysis will be conducted to calculate the cost-effectiveness of using shade cloth in tomato seed production.
A publication will be written with results and methods of the trials and Budget Analysis. Field days and a webinar will be conducted on shade cloth for tomato seed production.
Research Objective 1: In 2023 and 2024, evaluate the impact of shade cloth on tomato seed yield and quality in 10 replicated trials across three Western states.
Research Objective 2: Conduct Partial Budget Analysis to report on the change in profit from using shade cloth to improve tomato seed yield in 2025.
Educational Objective 1: Develop publication on the use of shade cloth to manage high temperatures in tomato seed crops and distribute to 100+ producers by 2025
Educational Objective 2: Develop a webinar on the use of shade cloth to manage high temperatures in tomato seed crops and present webinar to 100+ producers by 2025
Educational Objective 3: Host 5 Field Tours and Virtual Tours for 100+ producers by 2025.
Cooperators
- - Producer
- - Producer
- - Producer
- - Producer
- (Educator)
- - Producer
- - Technical Advisor (Educator and Researcher)
Research
Tomato seed shade cloth trials were grown on farms in 2023 and 2024 in Washington, California, and Arizona. These were grown as randomized complete blocks with 2 replications per site and two treatments per block: unshaded and shaded under 30% opacity shade cloth.
Each plot was 20 feet long. Tomato plants were planted at 18 inches between plants in-row, with between-row spacing of 4 to 5 feet, matching standard production practices at each trial site, with a target population of approximately 11,000 plants / acre.
Shade cloth was installed horizontally above each “shaded” plot. Temperature, precipitation and humidity data were collected on site using portable weather stations.
Trials were analyzed as replicated complete block design trials across all sites, using the following linear model for complete blocks:
Y = μ + Treat + Loc + Year + Rep(Loc x Year) + Loc x Treat + Year x Treat + Year x Treat x Loc + ε
Where μ = grand mean, Loc = location, Year = year, Rep = replication, Treat = shade cloth treatment, and ε = error. Location and treatment are considered as fixed effects, whereas year and replication are considered random. Means and confidence intervals were calculated using the emmeans R package
The partial budget was conducted based on the wholesale materials costs, the producer labor records of additional labor in installing, maintaining, and removing the shade cloth, and wholesale organic tomato seed prices based on industry standards for small- to medium- scale organic seed production (https://seedalliance.org/publications/seed-economics-toolkit/).
Tomato seed yields varied considerably across environments across replications, locations and years, from a low of 0.2 grams of seed per plot to a high of 356 grams of seed per plot. The major factor is these yield differences was the planting date, with late planted tomato seed plots in Arizona yielding considerably less. This amount of variation did not allow us to find significant differences between the shaded and unshaded treatments. However, the overall trend was that shading did improve seed yields, with unshaded plots yielding 73.8 grams per plot on average and shaded plots yielding 111.5 grams per plot on average.
Partial Budget Analysis
Although our trials showed no statistically significant differences in seed yield between shade and no-shade treatments, the average yields suggest a potential benefit. To determine whether the observed increase in yield justifies the added cost of installing shade cloth, we conducted a partial budget analysis.
The analysis compares two treatments: 30% shade cloth versus no shade. Plot-level data were scaled to the plant and acre levels to reflect practical implementation. We estimated net economic benefit based on:
- The mean increase in seed yield per 20-foot plot (0.0831 lb, or 37.7g)
- A wholesale organic tomato seed price of $400/lb (with sensitivity range: $280–$640)
- A plot cost of $285 for shade materials (shade cloth, T-posts, clips), amortized over 5 years, based on the average actual costs incurred by trial participants for shade cloth, materials and labor.
- A plot size of 100 ft² (20 feet long by 5 foot wide beds), containing 12 plants.
Partial Budget Summary
Per-Plot Analysis (20-foot plot)
|
Component |
Value ($) |
|
Additional revenue (0.0831 lb × $400/lb) |
$33.24 |
|
Annualized cost (materials ÷ 5 yrs) |
$57.00 |
|
Net economic impact |
−$23.76 |
Per-Acre Analysis
|
Component |
Value ($) |
|
Additional revenue |
$14,504 |
|
Annualized cost of shade system |
$24,852 |
|
Net economic impact |
−$10,348 |
Per-Plant Analysis
|
Component |
Value ($) |
|
Additional revenue (3.14g × $400/lb) |
$2.77 |
|
Annualized cost (per plant) |
$4.75 |
|
Net economic impact |
−$1.98 |
Sensitivity Analysis: Net Benefit per Acre
|
Seed Price ($/lb) |
Revenue Gain |
Net Benefit |
|
$280 |
$10,153 |
−$14,699 |
|
$400 (average) |
$14,504 |
−$10,348 |
|
$640 |
$23,206 |
−$1,646 |
The break-even seed price under current costs and yield increase is approximately $685 per pound.
Under the observed yield increase of 37.7g per plot, shade cloth was not economically beneficial at average seed prices ($400/lb).
Research Outcomes
This project suggests that shade cloth offers a promising tool for organic tomato seed production in the Western U.S., especially under high heat stress conditions. While not statistically significant, the yield improvements under shade were consistent, indicating that moderate shading can buffer crops against extreme temperatures during pollination and seed fill.
Given the increased risk of heat stress, we recommend that organic seed producers in high-risk regions consider incorporating 30% shade cloth into their production systems—particularly for sensitive tomato varieties or high-value seed lots.
Future research should explore:
-
Multi-year, multi-variety trials to enhance statistical power
-
Long-term cost-benefit analysis, including equipment reuse
-
Practical considerations for labor, durability, and reusability of shade systems
Such work will further inform the role of shade cloth in resilient, regionally adapted seed production systems.
Education and Outreach
Participation Summary:
To meet our educational objectives, the project team developed and implemented a multipronged outreach strategy. We compiled a literature review and integrated it with trial results to create a final publication for seed producers and educators. A webinar was produced and delivered to share trial outcomes, economic insights, and practical recommendations.
Field days were organized at three trial sites (one per state), and two additional virtual tours were conducted to expand reach. Each event included hands-on demonstrations and discussions with trial collaborators. Evaluation forms and feedback were collected where possible to assess knowledge transfer.
The education timeline included:
-
Spring 2023: Literature review, trial setup documentation
-
Summer/Fall 2023–2024: Field days and data collection
-
Winter 2024–2025: Publication writing, webinar recording
-
Spring 2025: Webinar hosted and shared
The final outreach products include:
-
1 publication: Producing Tomato Seeds Under Shade Cloth
-
1 webinar with over 30 live participants and 180 total views
-
6 in-person field days and 2 virtual tours, reaching over 140 producers and researchers.
Participant feedback from the webinar and tours highlighted the value of seeing real-world implementation and economic data. Producers reported increased confidence in experimenting with shade cloth and a better understanding of cost considerations.
Education and Outreach Outcomes
This project reinforced the value of blending on-farm research with multi-format education. Field tours and live events were especially effective in engaging producers and translating data into actionable knowledge. Virtil tours and webinars allowed us to reach a broader audience.
Future outreach on this topic should:
-
Continue to include economic analyses and planning tools
-
Offer region-specific examples for microclimate modification
These methods could help producers to evaluate its feasibility in their own systems.
Seed Production
Seed Physiology
Economic Analysis