Let's dive into the practical applications of frass in the field. Understanding which crops and plants have already benefited from frass can give us a solid foundation for future considerations. Here’s a bulleted list detailing some of the successful (and sometimes challenging) uses of frass on various plants and crops, directly from the sources:
Arugula: Showed highest fresh and dry weight, along with increased macronutrients (N, P, K, Mg) and improved micronutrients.
Insect Frass Species: Black soldier fly (BSFL), Mealworm
Basil (Ocimum basilicum): Increased plant growth; peat mixtures with 10% frass adequately replaced traditional peat-based growing medium; enhanced fresh weight and photosynthetic activity, even under drought conditions.
Insect Frass Species: Black Soldier Fly (BSF), Black soldier fly (HexaFrass™)
Barley (Hordeum vulgare): Showed great potential as a partial or complete substitute for mineral NPK fertilizer, with similar biomass yield and nutrient accumulation; significant increases in shoot growth, NPK, and chlorophyll density; plant growth promoted.
Insect Frass Species: Mealworm (Tenebrio molitor L.), Black soldier fly (HexaFrass™), Black Soldier Fly (BSF)
Bell pepper: Increased yield by 60% with cricket frass, 47% with desert locust frass, and 7% with black soldier fly frass compared to commercial NPK fertilizer.
Insect Frass Species: Cricket, Desert locust, Black soldier fly
Bermudagrass (Cynodon dactylon): Forage yield and quality were similar to conventional fertilizers, but soil fertility was substantially improved.
Insect Frass Species: Yellow mealworm (Tenebrio molitor L.)
Bok choi (Brassica rapa subspec. chinensis): Produced yields similar to mineral fertilizers.
Insect Frass Species: Black soldier fly (Hermetia illucens L.)
Brassica rapa: Initially, raw frass from both BSF and mealworm reduced growth and leaf area, but negative effects lessened over time with mealworm frass; incubation or composting of frass removed growth inhibition and increased leaf area. Application rates of 1/20–1/30 frass-to-soil were beneficial, but higher rates impaired growth.
Insect Frass Species: Black Soldier Fly (BSF), Yellow mealworm (MWF), Mamestra brassicae
Broccoli (Brassica oleracea): Evaluated for effects on growth, yield, and nutritional profiles.
Insect Frass Species: Black soldier fly (BSFFF) (solid, liquid, chitin-fortified)
Brussel sprouts (Brassica oleracea L.): Reduced cabbage root fly pest infestation.
Insect Frass Species: BSF frass or exuviae
Bush bean: Improved biological nitrogen fixation and sustainable production.
Insect Frass Species: Insect frass fertilizer
Cabbage (Brassica oleracea): No differences in growth and volume increase compared to commercial fertilizer; significant decrease in aphid presence and a 22% higher growth rate; growth and nutrient composition almost identical to commercial N fertilizer; produced similar yields compared to mineral fertilizers.
Insect Frass Species: BSF, IFF (Insect Frass Fertilizer), Black soldier fly (Hermetia illucens L.), Caterpillar frass, Cabbage looper (Trichoplusia ni), General insect frass
Cereal seedlings (general): Increased shoot growth.
Insect Frass Species: Insect frass fertilizer (general), Black soldier fly (HexaFrass™)
Cherry tomato: Increased fruit biomass.
Insect Frass Species: Mealworm
Chicory (Cichorium intybus): Increased growth, shoot dry matter, shoot regrowth, and 100% survival; optimal dose (4g per pot) improved plant development.
Insect Frass Species: ICOF (general, likely BSF frass), Frass (implicitly BSF)
Chilli pepper: Brewery waste biofertilisers performed better than poultry waste biofertilisers, especially with inorganic NPK fertilisers; comparable results to other fertilizers.
Insect Frass Species: Black soldier fly (BSF), BSFL
Chinese cabbage: Showed significantly strongest positive yield response; similar leaf count, length, width, and nutrient accumulation compared to commercial fertilizer; reduced phytotoxicity over time.
Insect Frass Species: BSF
Corn (Zea mays): Stunted plants with shorter growth and fewer leaves.
Insect Frass Species: BSF
Cowpea: Significantly reduced loss due to Fusarium wilt disease; enhanced yield and nutritional quality; activated plant defense responses.
Insect Frass Species: Black soldier fly (BSF), Edible insect frass (general), H. illucens
Cress (general, including garden cress): Frass was unable to suppress Rhizoctonia solani damping-off disease; did not decrease diseases caused by Rhizoctonia solani and Pythium ultimum.
Insect Frass Species: BSFL, H. illucens
Cucumber: Increased fruit biomass.
Insect Frass Species: Mealworm
Delia radicum L. (Cabbage root fly larvae): Raw BSFF reduced larval survival and pupal biomass; raw MWF increased larval survival and biomass.
Insect Frass Species: Black soldier fly (BSFF), Yellow mealworm (MWF)
Dragon fruit cacti: Negative effects on aerial part growth, but enhanced root development.
Insect Frass Species: Mealworm (fed with polystyrene)
Dwarf sunflower (ornamental plant): Significantly increased number of flowers.
Insect Frass Species: Mealworm
French beans (Phaseolus vulgaris): Combination of composted frass and NPK fertilizers delivered best results in growth, yield, N uptake, and nutrient use efficiency; sole application also positive; plant growth promoted.
Insect Frass Species: BSF (composted), Mealworm, Insect frass fertilizer
Green bean: Showed significantly strongest positive yield response.
Insect Frass Species: BSF
Helianthus annulus (Sunflower): Increased stem width and fat content in seeds; positive results from germination test and pot experiment.
Insect Frass Species: Black Soldier Fly larvae (BSFL), Tenebrio molitor
Herbs (general): Improved shoot and root growth, with similar effects to chicken manure pellets.
Insect Frass Species: Black soldier fly (HexaFrass™), BSF
Horticultural fungal pathogens (general): Observed inhibition in growth.
Insect Frass Species: BSF
Italian ryegrass (Lolium multiflorum): Boosted biomass yields by up to 17%; 10 Mg/ha was needed to increase N uptake and biomass compared with mineral fertilizer; showed increased soil organic matter, phosphorus, and potassium, leading to positive effects on crop productivity.
Insect Frass Species: BSF, Mealworm (Tenebrio molitor L.)
Kale: Combination of composted frass and NPK fertilizers delivered best results in growth, yield, N uptake, and nutrient use efficiency; sole application also positive; enhanced yield and nutritional quality; increased leaf biomass; greater biomass, stem diameter, and height, as well as increased macro and micro nutrients.
Insect Frass Species: BSF (composted), Edible insect frass (general), Mealworm, Frass (implicitly BSFL)
Komatsuna (Brassica rapa var. perviridis): Good quality and capable of improving soil nutrient availability, growth, and yield; produced similar yields compared to mineral fertilizers.
Insect Frass Species: Frass (general, from Kagata and Ohgushi 2012), Black soldier fly (Hermetia illucens L.)
Leafy greens (general): Improved nutritional quality, productivity, and greenness; improved rooting and growth performance; can replace 10–20% peat.
Insect Frass Species: BSFL, Superworms, Mealworms
Lettuce (Lactuca sativa): Significantly strongest positive yield response; improved growth parameters compared to urea and control; general application (20-30%) resulted in poor growth, except at 10% concentration; increased size; moderated white mold spread; increased shoot dry weight; grew better in soil amended with BSFF than urea or unamended soil; reduced growth compared to NPK fertilizer due to N immobilization; showed great potential as an organic fertilizer, providing macronutrients and increasing aerial biomass; favored seed germination and seedling growth.
Insect Frass Species: BSF, BSF (BSFF), BSF (okara-derived), Chitin supplements (frass contains chitin), Black soldier fly (HexaFrass™), Yellow mealworm (T. molitor), Black soldier fly (Hermetia illucens L.), Saproxylic-cerambycid larvae of Chlorophorus annularis, Frass (implicitly BSF)
Maize (Zea mays): Higher N uptake than commercial organic fertilizer; comparably low N-fertilization effects; green market waste biofertiliser did not significantly improve yield; successfully used to promote growth; negatively impacted plant growth (dwarf, fewer leaves); similar growth responses to chicken manure; increased grain yield; higher net income; potential to replace commercial fertilizers; significant increases in shoot growth; plant growth promoted; increased grain yields; chlorophyll content comparable to regular fertilizers; produced similar yields compared to mineral fertilizers; enhanced yield and nutritional quality; increased plant height and chlorophyll content.
Insect Frass Species: Black soldier fly (BSFFF), Black Soldier Fly (BSF), BSF (from green market waste), BSF (from poultry waste, brewery waste, green market waste), BSFL, Insect frass (general), IFF (Insect Frass Fertilizer), Black soldier fly (Hermetia illucens L.), Caterpillar frass, European corn borer (Ostrinia nubilalis), S. frugiperda
Microalgae Chlorella vulgaris: Suitable as a basis for growth medium; showed same growth pattern and protein content as conventional medium.
Insect Frass Species: Insect frass (general)
Nasturtium (ornamental plant and vegetable): Significantly increased number of flowers (as ornamental) and increased leaf biomass (as vegetable).
Insect Frass Species: Mealworm
Oak (trees): Increased tree heights and root collar diameters on light sandy soils.
Insect Frass Species: Insect frass (general)
Oats (Avena sativa): Significant increases in shoot growth, NPK, and chlorophyll density; optimal frass dose (7.1g) enhanced plant growth.
Insect Frass Species: Black soldier fly (HexaFrass™), BSF (from spent grain)
Onion plants: 20 tonnes per hectare of BSF frass significantly reduced height, indicating a phytotoxic effect.
Insect Frass Species: BSF
Ornamental plants (general): Can be used as organic fertilizer; wider use of mealworm frass appears beneficial and justified.
Insect Frass Species: Mealworm (Tenebrio molitor L.)
Pakchoi (Brassica rapa L.): Positive impact on plant growth, comparable to compost effects; produced similar yields compared to mineral fertilizers; improved performance.
Insect Frass Species: Black Soldier Fly larvae (BSFL), Black soldier fly (Hermetia illucens L.), BSF
Parsley: Increased shoot dry weight.
Insect Frass Species: Black soldier fly (HexaFrass™), BSF
Pepper: Similar growth responses to chicken manure; plants responded better with frass and chemical NPK fertilizer combination.
Insect Frass Species: BSF (from poultry waste, brewery waste, green market waste)
Perennial Ryegrass (Lolium perenne L.): No significant differences in growth compared to mineral fertilizer, indicating rapid action; increased shoot growth compared to control; increased shoot regrowth after cutting.
Insect Frass Species: Black soldier fly (BSFF), Black soldier fly (HexaFrass™)
Pines (trees): Increased tree heights and root collar diameters on light sandy soils.
Insect Frass Species: Insect frass (general)
Plantago lanceolata (Plantain): Increased growth, shoot dry matter, shoot regrowth, and 100% survival; optimal dose (4g per pot) improved plant development.
Insect Frass Species: ICOF (general, likely BSF frass), Frass (implicitly BSF)
Plutella xylostella L. (Diamondback moth larvae): Raw BSFF reduced larval survival; raw MWF increased larval survival.
Insect Frass Species: Black soldier fly (BSFF), Yellow mealworm (MWF)
Potato: Showed significantly strongest positive yield response; produced similar yields compared to mineral fertilizers; enhanced growth and yield.
Insect Frass Species: BSF, BSFCOF (Black Soldier Fly Compost Organic Fertilizer), Black soldier fly (Hermetia illucens L.)
Rape seeds: Reduced phytotoxicity over time, reaching germination index >66% after 13 days.
Insect Frass Species: BSF
Red clover: Boosted biomass yields by up to 17% compared to conventional composts and unamended soil.
Insect Frass Species: BSF
Rhizoctonia solani (plant pathogen): Frass extracts strongly or completely inhibited mycelial growth.
Insect Frass Species: Black soldier fly (BSFL)
Rice (Oryza sativa): Caterpillar frass-induced defenses; improved plant growth when combined with synthetic fertilizers; effects on growth and heavy metal migration; increased production yield; activated defensive responses.
Insect Frass Species: Caterpillar frass, BSFF, Hermetia illucens, BSF (from chicken manure), Fall armyworm (Spodoptera frugiperda)
Rubber trees: Resulted in 20% higher yield in pine resin acquisition.
Insect Frass Species: BSF
Ryegrass: Successfully used to promote growth; biomass significantly higher with frass, improving plant N nutrition; positive and steady growth with increased soil fertility; produced similar yields compared to mineral fertilizers; increased shoot growth and regrowth; crop yield favored by organic and mineral fertilizers; improved performance.
Insect Frass Species: Black soldier fly (Hermetia illucens L.), Mealworm (T. molitor L.), BSF, Black soldier fly (HexaFrass™)
Sclerotinia sclerotiorum (plant pathogen): Frass extracts inhibited mycelial growth.
Insect Frass Species: Black soldier fly (BSFL)
Seeds (general): Showed highest germination rate (>90%) and germination index (267%).
Insect Frass Species: BSF frass fertilizer
Shallots: Brewery waste biofertilisers performed better than poultry waste biofertilisers; similar growth responses to chicken manure.
Insect Frass Species: Black soldier fly (BSF) (from poultry waste, brewery waste, green market waste), IFF (Insect Frass Fertilizer)
Spinach (Spinacia oleracea): Increased organic matter and N uptake, significantly favored growth (six-fold higher biomass at 1% frass), highest chlorophyll content and photosynthetic efficiency; plant growth promoted.
Insect Frass Species: Yellow mealworm (Tenebrio molitor), General insect frass (cross-referenced to T. molitor)
Spring onions: Improved yields to the same extent as inorganic control; no clear differences between compost and frass in affecting soil fertility or plant growth.
Insect Frass Species: BSF
Sudan grass: Increased plant growth.
Insect Frass Species: BSF (reared on pig slurry)
Sweet banana peppers: Frass tea had effects on production and composition.
Insect Frass Species: Black soldier fly (BSF) larvae
Sweet corn: Increased fruit biomass.
Insect Frass Species: Mealworm
Sweet potato (Ipomoea batatas): Improved rooting and growth performance; potential to replace commercial fertilizers; produced similarities in growth parameters; cost-benefit ratio was higher using frass compared to inorganic fertilizer.
Insect Frass Species: Superworms, Mealworms, BSFL, Frass (implicitly BSF)
Swiss chard: Higher growth compared to unfertilized soil; production was higher compared to inorganic fertilizers.
Insect Frass Species: BSF (post-composting), BSF (from human faeces, food waste, cow manure)
Timothy (Phleum pratense L.): Increased shoot growth compared to control plants; increased shoot regrowth after cutting.
Insect Frass Species: Black soldier fly (HexaFrass™)
Tomato (Solanum lycopersicum): Reduced loss from Fusarium wilt disease; showed biostimulant/elicitor effects; comparable fruit yield, quality, plant biomass, and greenness; peat mixtures with 10% frass adequately replaced growing medium; comparable total yields, greenness, and biomass to control; caterpillar frass-induced defenses; enhanced yield and nutritional quality; increased fruit biomass; biomass increased rapidly with higher frass rates; frass inhibited Fusarium oxysporum root colonization and reduced disease severity; activated defensive responses.
Insect Frass Species: BSFL, Cricket frass (Acheta domesticus), BSF (composted), Caterpillar frass, Edible insect frass (general), Mealworm, General insect frass (cross-referenced to cricket frass), Tomato fruit worm (Helicoverpa zea), BSF
Triticale (Triticosecale): Significant increases in shoot growth, NPK, and chlorophyll density; optimal frass dose (6.8g) enhanced plant growth.
Insect Frass Species: Black soldier fly (HexaFrass™), BSF (from spent grain)
Vegetables (general): Can be used as organic fertilizer; improved shoot and root growth; N and P uptake comparable to commercial fertilizers; significantly higher (16-fold) edible plant parts compared to compost.
Insect Frass Species: Mealworm (Tenebrio molitor L.), Black soldier fly (HexaFrass™), BSFF, YMW
Wheat: Strong inhibitory effect on germination and plant growth from aqueous extracts.
Insect Frass Species: Mealworm
Winter wheat (Triticum aestivum): Produced similar yields compared to mineral fertilizers.
Insect Frass Species: Black soldier fly (Hermetia illucens L.)
Zinnia (ornamental plant): Significantly increased number of flowers.
Insect Frass Species: Mealworm
Zucchini (Cucurbita pepo L.): Considerably taller, with bigger leaf area and dry leaf weights compared to unamended sandy soil; improved cultivation.
Insect Frass Species: BSFF, MWF, Insect frass (general, implies BSFF and MWF), Mealworm