This large Michigan cultivator contacted Willow with ongoing failures for total yeast and mold. Despite the 100,000 CFU/g limit in Michigan, the on-site team continued to struggle with compliance woes and were ultimately able to trace many of their issues to the facility’s irrigation system.

Upon connecting with members of Willow’s sales team, the cultivation staff was excited to learn that beyond offering the WillowPure 360 as a decontamination tool, as a part of their lease the Willow Science Team would travel on-site to their facility to conduct environmental testing and assist with the diagnosis of contamination sources. They signed a 3-year lease and were thrilled to get started. 


The Willow science team conducted a microbial assessment of the cultivation facility, swabbing contact surfaces, collecting physical raw material samples, and performing air quality tests throughout each room within the cultivation facility. They paid close attention to the irrigation system – collecting physical water samples in addition to swabbing driplines, runoff, and holding tanks. 

The results of the assessment indicated that the water being used on site was not properly filtered prior to deployment through the irrigation system. As a result of this baseline contamination, a biofilm had built up within the driplines and internal irrigation piping, resulting in highly contaminated water that bred endophytic contamination within the vascular system of the plants. 

The Willow Science Team prescribed a variety of cleaning solutions and SOP’s for maintaining the irrigation system and removing the biofilm that had built up. Additionally, having learned about the efficacy of ozone in destroying microbial contamination, the cultivation team opted to implement an ozonated water system to better ensure that their water remained contamination-free throughout the cultivation process.

Follow-up testing was performed following the adoption of these systems to ensure that the water and irrigation lines were indeed showing more limited levels of contamination. 


Following the validation of the ozonated water system in conjunction with the implementation of the WillowPure360, the cultivation staff was thrilled to see their compliance rate shoot through the roof. Within just a few weeks, they were passing nearly 100% of their tests on the first round. With the focus on clean upstream practices and the WillowPure 360 as their gentle and proactive decontamination step, this cultivator now has long-term confidence in their clean cannabis. 

With further environmental surveys and the creation of an in-house quality assurance team, following the guidance of the Willow Science Team, this cultivator continued to excel. Beyond simple compliance testing, the improvement of their in-house irrigation system and the elimination of endophytic contamination led to more vibrant, healthier, and ultimately higher-yielding plants across their cultivation space. Another compliant partner, another source of contamination eliminated, and another Willow success story.

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