Stronga were recently approached by a client who had one key question in mind – would it be an effective use of energy and resource to steam pasteurize and reuse a large stockpile of spent peat moss blend they had built up, outside the greenhouse, over 9 years? As a well-established company and one of the largest legal cannabis cultivation centres worldwide, it was important that their chosen steam pasteurization process would maintain their integrity and high standards. Stronga ensured they would endeavour to uphold these principles.

After an in-depth discussion with the client in which we determined their current growing methods, substrate details, weekly consumption, and harvesting and transplanting quantities, the team at Stronga established a full understanding of the capacity and steam requirements, enabling a solution to be designed to suit their requirements.

The client used a specific peat moss/coir/Perlite blend as their growing substrate - a light bulky growing medium. Despite being fairly disease-resistant and suitable for growing young plant crops, the peat moss element of the blend is non-renewable. With peat-based substrates increasing significantly in cost, we calculated the client’s substantial annual cost savings over $100,000, waste reductions and profit gains through heat treating the stockpile of substrate which had formed over the years. In total, the client would release several $100,000’s of value.

Having the capability to reuse their spent growing substrate could prove game-changing for this client who was cultivating, harvesting and selling their products to large numbers of consumers across the US. At the time of writing, the client currently uses approximately 300 cubic feet of compressed substrate blend a week, harvesting 650 plants and transplanting at least 2,000 plants in the same time, within their vast 100, 000 sq. ft. production site. They are planning to use the FlowSteama to clean the otherwise wasted peat moss blend and then re-plant and use it again, almost immediately after the steam process is finished (sterilisation in this case is completed at 80‘C for 30 minutes).

We anticipate this will be a hugely beneficial change for the client who will be empowered to take control of their own circular growing process and reap the many benefits of in-house recycling that would accompany this, including the economic value, swiftness of process and organic approach to pest avoidance.

Whilst the client was keen to begin their substrate steam-cleaning journey right away, they did have concerns over the problems they had previously dealt with in their growing substrate, this included the pathogens; Hop Latent Viroid parasite and Fusarium fungus, among others which had often infested material during the growing cycle and whilst in storage.

Stronga’s FlowSteama offered an opportunity for the client to organically pasteurize their substrate and reduce the risk of losing significant crop yields through inadequate pest control. The losses associated with a pest or disease infestation on crops can be catastrophic - time, money, material, and crops can all be lost, as well as disappointing customers waiting for their product.

FlowSteama empowers Cannabis growers to stay one step ahead by pasteurizing the growing substrate before use. This dramatically reduces the risk of losing crops by eliminating all unwanted pathogens, including the ones that particularly concerned this client. Using their own stockpile of spent growing media, instead of purchasing additional imported virgin substrate, would provide significant financial benefits for this client but it would also provide complete awareness about where the material has come from, reducing the chance of potentially hidden risks.

Stronga have experience in addressing client’s concerns about ‘Fusarium’. We know that steaming at 80’C for as little as 30 minutes is sufficient to remove Fusarium and most other virus’, bacteria and weed seeds from the growing media. By removing this fungus, the client is also removing the risks associated with it, including plant wilting and any potential toxic effects to humans.

The client’s other main concern for their Cannabis growing business was ‘Hop Latent Viroid’ which is particularly destructive and persistent. In 2021, the legal marijuana industry was valued at USD13.2 billion. It was estimated that there were losses of at least 4 billion in that same year due to Hop Latent Viroid alone. Hop Latent Viroid is rightly a major concern to cannabis growers; Stronga are happy to discuss this further with other Cannabis / hemp growers to ease any concerns. The image below was adapted from a diagram by ‘Medicinal Genomics’.

Moreover, Hop Latent Viroid dramatically reduces cannabidiol content concentrate in Cannabis plants. It is estimated that the reductions are anywhere between 50-70%, making the final crop undesirable for customers and businesses that look for products with high levels of THC. The viroid causes dudding disease and stunted growth which both affect the overall crop. Usually spread through infected plant sap, cloning, seeds and water, the pathogen thrives on poor sanitation techniques, producing copies of the viroid and spreading through the whole crop. Hop Latent Viroid uses up the plant’s energy and significantly reduces the crop’s value, restricting the cannabinoids the plant can produce.

Although there is a consensus about how to deal with Hop Latent Viroid and specific testing is beneficial, research shows heat treatment to be an effective solution in reducing the level of viroid. FlowSteama gives the client control over their yield and crop quality while also allowing them to reuse their growing substrate multiple times over. Whilst also being organic and pesticide-free, steam heat treatment is historically proven in pasteurizing substrates. It removes all harmful pathogens whilst even helping limit the harmful effects of Hop Latent Viroid. Incubation of Hop Latent residues at temperatures of 70‘C indicate a dramatic reduction of the viroid in affected crop after 1 day, and should be used as a pre-treatment method in order to reduce potential future costs and losses. Stronga’s heat treatment systems comfortably reach temperatures of 80’C and are therefore highly capable of eliminating the viroid, reducing losses and increasing profits.

If pathogen control wasn’t assurance enough, FlowSteama also offers many other benefits for businesses. For this particular client, the main benefit was that the organic steam pasteurization process allowed them to reuse their valuable spent heap of peat moss over and over again. This would reduce their high material import costs whilst also reducing labour hours. FlowSteama provides assurance that cannabis growing cycles run as economically and hygienically as possible, allowing the grower to focus on producing the best quality final crop rather than worrying about their growing substrate.

By using steam - a low cost approach to organically killing harmful bacteria, pests and weed seeds - the client is able to reduce crop disease and reduce single-use substrate costs, saving time and reducing waste in their business. This allows for stability in their production and helps maintain excellent customer relationships by distributing pesticide-free products.

Stronga uses a superheated, triple-pass boiler low-pressure steam boiler system alongside the FlowSteama vessel. The value offered by this type of arrangement include:

1. The Stronga steam boiler requires only 11% more energy to increase the temperature of the steam by 100’C to 200’C. Steam is super-heated for improved penetration ability using only a small amount of extra energy.
2. The FlowSteama is extremely well-insulated so the temperature is retained in the vessel with no energy lost to the atmosphere. Once the substrate has fully absorbed the steam and the target temperature has been reached, the boiler automatically modulates down to prevent energy losses or unnecessary fuel costs.
3. FlowSteama’s unique moving floor PulseWave™ system agitates and mixes the substrate during the heat treatment process to ensure the output is uniformly pasteurized.
4. FlowSteama is a closed system which ensures energy retention while also limiting potentially disastrous contamination risks. This allows clients to be in complete control of their substrate sanitation process.

5. The logging and live monitoring feature on the HMI ensures the client can observe the heat treatment process and adjust “time at temperature”, if necessary. This feature also provides evidence that the peat moss blends have been treated at the correct temperature for the required duration.
6. FlowSteama and SteamBoila use a low amount of fuel and, when compared to the importation of single-use substrates, is far more economical and environmentally-friendly.
7. FlowSteama’s heat recuperation process allows for even more energy conservation and offers significant savings in fuel consumption.

By choosing to invest in FlowSteama, legal Cannabis growers gain an invaluable addition to their business. FlowSteama has proven over the years to be extremely efficient and effective in pasteurizing growing substrates. It is the ideal solution to sanitize spent growing substrates before reuse.

After much discussion between the client and Stronga’s ‘clean-steam’ team, we were able to design a bespoke system that would provide significant improvements to the client’s Cannabis growing operation. Stronga encourages customers to contact our team so we can be better equipped to understand and answer any questions.

Begin the journey of reusing your growing substrate today – info@stronga.co.uk

Bibliography:
1. Hagemann, Michael Helmut, ‘Degradation of hop latent viroid during anaerobic digestion of infected hop harvest residues’.
2. Matousek, Jaroslav, ‘The Variability of Hop Latent Viroid as Induced upon Heat Treatment’.
3. Medicinal Genomics.
4. Saldi, Tassa, ‘Hop Latent Viroid (HLVd) & Pathogen Diagnostics: A Comprehensive Overview’.
5. Smith, Nicola, ‘An Overview Of The United Kingdom’s Legal Marijuana Industry’.
6. Taylor-Laine, Sarah, ‘Committee Blog: Hop Latent Viroid (HLV) – Overview of Pathogen Biology, Spread, Control, and Testing’.