LED Grow Light that Also Kills Cannabis Mold and Yeast


Total yeast and mold count is the scientific way to count and report the population of live bacteria or yeast and mold per gram of cannabis product. A total yeast and mold failure can be a devastating blow in the world of cannabis cultivation (Amirault, 2023). Fungi contamination can affect the entire supply chain, causing financial losses and a loss of reputation. But fear not, for there’s a game-changer on the horizon: the Boulderlamp MoonWalker LED grow light. It’s not your typical grow light; it’s a revolutionary ally in the battle against mold and yeast. While your cannabis crop thrives under its full-spectrum light, the MoonWalker’s purple-blue cycling beam is waging a silent war against these stubborn adversaries. For commercial cultivators, this dual-action wizardry is nothing short of a financial lifeline.

Yeast, Mold, and Fungi Associated with Cannabis Plants

The cannabis plant isn’t immune to the charms of yeast, mold, and fungi, with familiar foes like Sclerotinia sclerotiorum, Epicoccum nigrum, Cladosporium herbarium, Botrytis cinerea, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and Aspergillus terreus lurking in the shadows. Pathogens infecting cannabis plants reduce the growth of the crop. They attack the roots, crown, and foliage. Root and stem rot, bud rot, and powdery mildew are common fungal diseases affecting cannabis. There are no cannabis varieties resistant to powdery mildew.

Bacterial Contamination is Bad

Cannabis plants can also fall victim to bacterial contamination, with issues arising during cultivation, harvesting, drying, curing, or extraction. Contaminated cannabis can have harsh, chemical-tasting smoke and can lead to serious health issues when ingested, including fever, abdominal cramps, nausea, vomiting, and diarrhea. The potential human toxicity profile is alarming, encompassing acute and longer-term morbidity (Dryburgh et al. 2018; McGuinness 2009; Tashkin 2005). The effect of smoking, vaping, or inhaling contaminated marijuana poses greater risks to patients, especially those with leukemia, lymphoma, AIDS, or those with medical conditions requiring immune-suppressing therapies. “Immunocompromised patients including those receiving chemotherapy are at a higher level of risk to all microorganisms, where even low levels of microbial contamination can lead to a fatality”, (Gaudino).

Examples of Recent Recalls of Cannabis Products

To illustrate the severity of the problem, consider recent recalls published in MMJ Daily (Aug 25 and Aug 28, 2023). An Arizona establishment voluntarily recalled products due to possible Aspergillus contamination. Meanwhile, the Colorado Department of Revenue and the Colorado Department of Public Health and Environment issued a Health and Safety Advisory due to unsafe levels of Total Yeast and Mold in regulated marijuana flower. Cannabis product recalls can have a significant financial impact on a business and can also negatively impact a company’s reputation. In 2021 Michigan Marijuana Regulatory Agency recall affected over 65,000 pounds of cannabis flowers worth more than $200 million.

Purple-Blue Light – A Magic Bullet?

Purple-blue light is good for photosynthesis but 405 nm, for example, also possesses antimicrobial properties against a wide range of bacterial and fungal pathogens. 405 nm light is known to eliminate 90-99% of bacteria without harming cannabis growth and surroundings. “A large body of scientific evidence is now available that provides underpinning knowledge of the 405 nm light-induced photodynamic inactivation process involved in the destruction of a wide range of prokaryotic and eukaryotic microbial species, including resistant forms such as bacterial and fungal spores” (Maclean et al. 2014). A prior study noted, “High-intensity 404-nm light has been successfully applied for the inactivation Saccharomyces cerevisiae, Candida albicans, and dormant and germinating spores of Aspergillus niger” (Murdoch et al. 2013).

405 nm Light – How does it kill bacteria and fungal cells?

The magic of 405 nm light lies in its oxygen-dependent reaction. This wavelength excites photo-reactive molecules within microorganisms, leading to the production of cytotoxic oxygen-derived species. These species wreak havoc on cellular structures, damaging proteins, lipids, and nucleic acids, ultimately causing cell death (Amondeo et al. 2022; Maclean et al. 2009; McKenzie et al. 2016; Maclean et al. 2008). 405 nm antimicrobial light has another important advantage. Drug resistance in bacteria is a serious threat to public health on a global scale, as multidrug-resistant bacteria continue to emerge, however, studies find bacteria do not develop resistance to 405 nm antimicrobial blue light, (Haridas et al. 2022).

Light Intensity and Duration are Keys

The effectiveness of 405 nm light against mold and yeast depends on two factors: light intensity and duration. The following tables illustrate the inactivation kinetics of bacteria exposed to 405 nm light (Sinclair et al. 2023), for Escherichia coli and Salmonella enterica.

c. Escherichia coli

exposure time

f. Salmonella enterica

exposure time

The above and other tables in the study provide conclusive evidence of the antibacterial efficacy of 450 nm purple-blue light.

Advances in LED Technology: A Growing Revolution

The world of cannabis cultivation is undergoing a remarkable revolution thanks to advances in LED technology. In the past, traditional lighting sources like high-pressure sodium (HPS) were the go-to choice, but they had limitations. With the advent of LED grow lights, cultivators gained unprecedented control over the light spectrum and light intensity. These newfound flexibilities have allowed for significant strides in energy efficiency, crop yield and crop quality enhancement, and, also the management of pests, mold, and bacteria. LED grow lights are becoming the cornerstone of modern cannabis cultivation, offering a spectrum of benefits that were once unimaginable with older technologies like HPS. Leading the charge in this LED revolution is the patented MoonWalker LED grow light, a groundbreaking solution that takes cannabis cultivation to the next level.

MoonWalker LED Grow Light

cycling beam light

MoonWalker is a full-spectrum and high-efficiency LED grow light. A commercial cultivator in Boulder, Colorado who has been using MoonWalkers since early 2022 quoted this, “Gorgeous structure, size, trichomes, and everything”. What sets the MoonWalker LED grow light apart from the rest is its innovative cycling beam, alternating between different light bars during the growth cycle. This MoonWalking cycling beam, featuring 405 nm and other LEDs, allows for the use of high-intensity light without harming plants. MoonWalker’s full-spectrum light in combination with the cycling beam provides illumination during long daily lighting periods in the vegetative and flowering phases, which are typically 18 hours and 12 hours respectively. These long hours of operation and the cycling high-intensity 405 nm cycling light create a formidable weapon against cannabis mold and yeast on the surface and in the air.


The battle against mold, yeast, and bacterial contamination in cannabis cultivation is a relentless one. Yet, with the MoonWalker LED grow light’s pioneering technology, cultivators have an extraordinary tool at their disposal. As cannabis continues to thrive under its full-spectrum embrace, the MoonWalker’s 405 nm cycling beam silently but effectively eliminates these threats. It’s not just about growing more; it’s about growing better, safer, and more profitable. With the MoonWalker, cultivators can embrace the future of cannabis cultivation with confidence.


Ben Amirault: https://medicinalgenomics.com/5-factors-causing-cannabis-to-fail-total-yeast-and-mold/
MMJ Daily, Aug 25, 2023: https://www.mmjdaily.com/article/9554038/us-az-cannabis-products-recalled-due-to-possible-aspergillus-contamination/
MMJ Daily Aug 28, 2023: https://www.mmjdaily.com/article/9554408/us-co-flowers-recalled-due-to-yeast-and-mold/
Dryburgh et al. 2018: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6177718/
Dryburgh et al. 2018; McGuinness 2009; Tashkin 200
McGuinness 2009: https://journals.healio.com/doi/10.3928/02793695-20090902-03
Tashkin 2005: https://pubmed.ncbi.nlm.nih.gov/29953631/
Gaudino: https://www.edrosenthal.com/the-guru-of-ganja-blog/the-dangers-of-microbial-contaminants-in-cannabis-and-how-to-prevent-mold-and-mildew
Murdoch et al. 2013: https://pubmed.ncbi.nlm.nih.gov/23931117/
Amondeo et al. 2022: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9691702/
Maclean et al. 2009: https://journals.asm.org/doi/10.1128/aem.01892-08
Haridas et al. 2022: https://www.frontiersin.org/articles/10.3389/fmed.2022.905606/full
McKenzie et al. 2016: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5068139/
Sinclair et al. 2023: https://link.springer.com/article/10.1007/s12553-023-00761-3