Use OMRI-listed biofungicides for organic mold prevention
Several OMRI-listed (Organic Materials Review Institute) biological and natural fungicides are approved for use on food crops and provide effective mold control without synthetic chemicals. These products are suitable for commercial growers selling organic microgreens.
Peroxyacetic Acid Products
ZeroTol 2.0 (BioSafe Systems) -- See dedicated solution for full dilution rates - Hydrogen peroxide + peroxyacetic acid - OMRI listed, 0-day PHI, no residue
OxiDate 2.0 (BioSafe Systems) - Similar chemistry to ZeroTol, includes seed treatment labeling - OMRI listed, 0-day PHI
SaniDate 5.0 (BioSafe Systems) - Surface sanitizer and produce wash - Effective at 40 ppm for human pathogens in wash water - OMRI listed, NOP compliant - Also treats irrigation water and evaporative coolers
Biological Fungicides (Living Organisms)
Cease (BioWorks) -- Bacillus subtilis strain QST 713 - Controls both fungal and bacterial pathogens - OMRI listed, NOP approved - 4-hour REI, can be sprayed up to and on the day of harvest - Effective against damping-off, botrytis, powdery mildew - Living bacteria colonize plant surfaces and outcompete pathogens
Double Nickel 55/LC (Certis Biologicals) -- Bacillus amyloliquefaciens strain D747 - Controls foliar and soil-borne diseases via 5 modes of action - OMRI certified - No resistance issues, no residue - Low application rates - Effective against Pythium, Rhizoctonia, Fusarium -- the key damping-off pathogens
RootShield Plus (BioWorks) -- Trichoderma harzianum + Trichoderma virens - Specifically targets soil-borne root rot pathogens - University research (published in Crop Protection journal) tested this on microgreen root rot caused by Pythium aphanidermatum and P. dissotocum - Applied as a growing media drench - Preventative only -- will not rescue active infections
Plant Extract Fungicides
Regalia CG (Marrone Bio Innovations) -- Giant Knotweed extract (Reynoutria sachalinensis) - Activates the plant's own defense mechanisms (Induced Systemic Resistance) - OMRI approved, NOP compliant - Works on both foliar and soil-borne pathogens - Boosts plant vigor and growth while providing disease resistance - Must be applied preventatively before infection occurs
MilStop -- Potassium bicarbonate - OMRI listed, kills powdery mildew on contact - 25-35% more effective than sodium bicarbonate (baking soda) - Safe for food crops, low toxicity
Physan 20
- Quaternary ammonium compound -- broad spectrum algaecide, fungicide, bactericide, virucide
- For plant cuttings/seedlings: 1.5 teaspoons per gallon of water
- For surface disinfection: 1.5 tablespoons per gallon
- Not OMRI listed -- not approved for organic production
- Measure precisely; never estimate -- crop damage occurs at higher concentrations
- More commonly used for orchids and greenhouse sanitation than food crops
Tips
- Biological fungicides work best as preventatives -- apply before mold appears
- Pythium species that attack microgreens have developed resistance to synthetic fungicides like mefenoxam, making biologicals increasingly important
- For commercial microgreen operations, combining Cease or Double Nickel (biologicals) with ZeroTol (oxidizer) provides both preventative and curative coverage
- Keep records of product applications for organic certification audits
Other solutions for How do I prevent and treat mold on microgreens?
- Control airflow, humidity, and temperature to prevent mold environmentally
- Identify mold vs. root hairs and know common mold species
- Sanitize trays and equipment between every growing cycle
- Choose the right growing medium to minimize mold risk
- Use proper seeding density and bottom watering to prevent mold
Related content
- What growing medium and containers should I use? problem
- Use seed-starting soil for robust varieties solution
- Use ZeroTol 2.0 or OxiDate 2.0 for commercial-grade mold control solution
- Use hydrogen peroxide spray to treat active mold on microgreens solution
- Sanitize seeds before planting to eliminate mold spores solution