Growth Trials on Vegetables, Herbs, and Flowers Using Mealworm Frass, Chicken Manure, and Municipal Compost

Abstract

With the growth of the insect farming industry, increasing quantities of insect manure (called frass) must be upcycled. This research provides one of the first sources of information regarding the potential plant growth enhancement of Tenebrio molitor's frass on garden plants. It aims at demonstrating that frass is a promising fertilizer for plant production. Nine vegetables, one herb, and three flowers were planted on the roof of "La Centrale Agricole" in Montreal. Plants were grown in a 5% compost-enriched substrate (v/v) (control) and fertilized with 0.5% (v/v) frass (treatment 2) or an isonitrogen concentration of hen manure (treatment 3). Plant growth (germination, height, N flowers) and productivity (biomass) were assessed regularly throughout the growing season. Although beets and carrots' seedling emergence was inhibited by both manures, this did not lead to reduced edible biomass compared to the control (germination was unaffected for corn, radish, and arugula). Similar to hen manure, frass resulted in a 16-fold increase of the edible biomass as compared to the control. Frass-fertilized plants had larger and more numerous flowers than control plants. Our results confirm that insect manure should be recognized as a suitable fertilizer for multiple crops, and should be regulated like other manures.

Opportunities and challenges in upcycling agri-food byproducts to generate insect manure (frass): A literature review

“…A study comparing mealworm frass to isonitrogen concentration of chicken manure suggest similar biomass production are achieved in a variety of herbs and vegetables (Hénault-Ethier, Reid et al 2023). Hen manure fertilization may yield 26% more lettuce than BSF frass (Caron-Garant, Massenet et al 2022).…”

“…Trials on vegetable crops suggest that frass (from BSF) and compost enrich the soil and affect plant growth in a similar way (no statistical difference was observed at application rates ranging from 5 to 20 tons per hectare) (Zahn and Quilliam 2017). Adding frass (mealworm) to compost-amended potting soil significantly increases plant growth (Hénault-Ethier, Reid et al 2023).…”

“…The seedling phytotoxicity (germination rate) of composted mealworm frass appears to be related to the type of feed given to the larvae (corn straw ˃ wheat bran ˃ rice straw) (He, Zhang et al 2021). The effect of incorporating wheat bran-fed mealworm frass (0,5% v/v, 3-4-2) or chicken manure (iso-nitrogen) in potting soil amended with municipal compost (5% v/v) was evaluated on 9 vegetable and 3 flowering plants (Hénault-Ethier, Reid et al 2023). Seedling emergence was inhibited by both manures in beets and carrots (but not corn, radish and arugula), but this did not result in a decrease in edible biomass compared to the control.…”

Insect-based agri-food waste valorization: Agricultural applications and roles of insect gut microbiota

“…The application of YMW frass was found to increase edible biomass by up to 16-fold and produce larger and more abundant flowers. These promising results suggest that YMW frass could be a sustainable alternative to traditional fertilizers in various crop systems [ 86 ].…”

Is Sustainable Consumption a Sufficient Motivator for Consumers to Adopt Meat Alternatives? A Consumer Perspective on Plant-Based, Cell-Culture-Derived, and Insect-Based Alternatives

“…Frass, the primary by-product of insect farming, is an effective organic fertiliser that can enhance soil fertility. Using frass could reduce reliance on chemical fertilisers, which are linked to water pollution and soil acidification, and contribute to a minimal waste and emissions profile of insect farming [ 11 ]. These benefits make insects a viable and sustainable alternative to conventional meat production, requiring less land and water and exhibiting rapid growth rates, making them an appealing option for sustainable agriculture [ 12 , 13 ].…”