Optimizing mealworm by-products and plasma-activated water (PAW) to reduce nitrogen fertilizer usage in greenhouse transplant production systems

Commodities

• Vegetables: tomatoes

Practices

• Crop Production: application rate management, fertilizers, greenhouses, irrigation, nurseries, nutrient cycling, nutrient management, tissue analysis
• Education and Training: decision support system, demonstration, extension, networking, technical assistance
• Energy: byproduct utilization, energy conservation/efficiency, renewable energy
• Production Systems: other
• Soil Management: nutrient mineralization, organic matter, soil analysis, soil chemistry, soil quality/health
• Sustainable Communities: partnerships

Producers must deliver highly uniform, market-ready transplants while managing rising fertilizer costs and increasing scrutiny of nitrogen losses. In plug systems, frequent irrigation and low substrate buffering drive inefficient nitrogen use and preventable economic waste. However, growers still lack validated, commercially compatible strategies that reduce nitrogen fertilizer without sacrificing crop performance. This project asks: Can optimized mealworm frass and exuviae, combined with PAW, maintain commercial tomato transplant quality under reduced synthetic nitrogen fertilizer inputs?

We will conduct replicated greenhouse trials to (1) optimize frass and exuviae incorporation rates in soil substrate, (2) evaluate optimized frass and exuviae rates applied individually and in combination, (3) test interactions with PAW irrigation, (4) identify fertilizer-reduction thresholds that preserve transplant quality, and (5) quantify substrate nitrogen dynamics and leachate losses using non-destructive and chemical analyses. This approach is creative because it deliberately links two emerging strategies: circular nutrient recovery from insect production and decentralized nitrogen source generation via PAW. Expected outcomes include validated amendment rates, quantified nitrogen-reduction thresholds, and improved nitrogen use efficiency while maintaining transplant uniformity. This will deliver practical, science-based decision tools that help producers reduce synthetic fertilizer dependence without compromising commercial performance.

Research objective:

Objective 1: Identify optimal rates of exuviae and frass as soil amendments.

Objective 2: Determine effects of exuviae and frass optimized rates separately and combined on transplant.

Objective 3: Evaluate synergistic effects of plasma-activated water and amendments on transplants.

Objective 4: Quantify synthetic nitrogen reduction thresholds under optimized systems.

Objective 5: Characterize nitrogen dynamics and potential loss pathways.

Educational objectives:

Objective 6: Develop and disseminate grower-focused educational resources.

Objective 7: Communicate findings and evaluate stakeholder engagement outcomes.