Improving Soil Moisture, Heat Resilience, and Yield Stability in Spinach, Kale, Carrots, and Okra Using Vermicompost and Worm Tea

Commodities

Practices

• Crop Production: nutrient management, water management
• Soil Management: soil quality/health

Safari Farms, a vegetable farm in Boise, Idaho, faces major production losses due to extreme summer heat, rapid soil-moisture decline, and low organic matter in its sandy soils. Key crops-spinach, kale, carrots, and okra-wilt, bolt early, and experience reduced yields during 95-105°F heat events. These challenges threaten farm income and reduce the farm's long-term sustainability. The research question guiding this project is: Can vermicompost and worm-tea applications improve soil moisture, reduce heat stress, and increase yields in heat-sensitive vegetable crops?

To address this, the project will compare three treatments-vermicompost, vermicompost plus worm tea, and an untreated control-using nine replicated field plots. The farm will measure soil moisture, leaf temperature, wilting severity, bolting rate, irrigation use, and total crop yields throughout the growing season. This practical, farmer-led research will identify which biological amendment provides the greatest improvement in soil water-holding capacity and crop performance under heat stress. The project directly responds to WSARE priorities by improving soil health, and supporting the success of beginning and low-resource farmers.

Expected outcomes include:

• Higher soil moisture retention and improved water infiltration
• Reduced heat stress indicators, including lower leaf temperatures and decreased bolting
• Increased marketable yields of spinach, kale, carrots, and okra
• Reduced irrigation labor and water use
• Stronger soil-health knowledge among growers

Project results will be shared through two multilingual field days, hands-on demonstrations, and simple soil-health guides translated into multiple languages. Findings will also be shared through the Local Farmer Network, partner organizations

RESEARCH OBJECTIVES

1. Evaluate the effects of vermicompost and worm-tea applications on soil moisture retention, infiltration rate, and water-holding capacity in heat-stressed vegetable beds.
   
   
2. Measure crop heat-resilience indicators-including leaf temperature, wilting severity, canopy color, and bolting rate in spinach and kale-to determine whether biological amendments reduce visible heat stress.
   
   
3. Compare total and marketable yields of spinach, kale, carrots, and okra across vermicompost, vermicompost + worm tea, and control treatments to identify the most effective practice under extreme heat conditions.
   
   
4. Assess changes in soil health indicators-organic matter, nutrient availability, microbial activity, and soil temperature-before and after the trial to quantify biological improvements from amendments.
   
   
5. Document irrigation volume, frequency, and labor time to evaluate whether soil health improvements reduce the farm's overall water and labor demands.
   
   
6. Identify which biological amendment (vermicompost, worm tea, or combined application) delivers the strongest improvements in soil function, plant vigor, and heat tolerance under real farm conditions.
   
   

EDUCATION / OUTREACH OBJECTIVES

1. Deliver two hands-on, multilingual field days demonstrating vermicompost production, worm-tea brewing, application methods, and practical strategies for managing crop heat stress.
   
   
2. Develop soil-health guides with step-by-step visuals and recommended rates to help growers adopt low-cost regenerative practices.
   
   
3. Produce a short video tutorial documenting treatment setup, monitoring methods, and final results for distribution through agriculture networks and local farm organizations.
   
   
4. Increase adoption of regenerative, biologically based amendments among small-scale farmers by demonstrating simple methods that improve crop resilience and reduce risk.
   
   
5. Share results widely through partner organizations, community gardens, the Local Farmer Network, Tribal food sovereignty programs, and regional food hubs to expand access to soil-health knowledge.
   
   

Build producer confidence, decision-making ability, and technical capacity by providing clear, replicable practices that help farmers reduce crop loss during extreme heat events.