It is best to have separate rooms for your mother, clone, and veg plants to provide optimum growing conditions while reducing cross-contamination. If you must run a combined mixed-use nursery, Anders states, “We often see these being three tiers with the bottom tier taller to house mother plants and the top two tiers shorter to hold veg plants.” For dedicated mother rooms, we have seen growers shifting away from single-tier, six months to a-year-old mother plants to double stacking smaller to medium mother plants with a shorter lifespan. The smaller, shorter lifespan mother approach provides more supple cuttings than woody cuttings from old moms and reduces the risk of pest and pathogen accumulation.
Michael explains his process of double stacking mother plants, “generally, I’ll keep my younger mothers on the top elevation, and that elevation will be a shorter elevation, the bottom elevation, which will be a taller elevation so that I can hold my more mature mothers.” He explains that having younger mother plants in your cycle is nice to have fewer issues. Michael can get a significant increase in better “A-grade” cuttings versus the older mother plants. With the older plants, you would need to get cuttings from the inside or the outside where lighting levels aren’t the same. Mother rooms can vary in size depending on how many genetics the grower wants to have available to rotate through production. Double-stacked mother rooms help house additional genetics in a smaller space, allowing you to allocate square footage for flower production.
Clone Rooms are relatively straightforward, with most growers opting to propagate clones on triple-tier wire mesh shelving carts. This “clone cart” design allows growers to fit a lot of clones in a small space. Depending on your cloning SOP and tray inserts, you can fit between three to six hundred clones on one cart. If you do not have a dedicated clone room, Anders prefers to “house the clone carts on the side of the veg-room rather than in the mother room.” This allows you to enter the mother room less frequently and protect your valuable genetics from unnecessary risk.
Veg rooms are the most common rooms growing multi-tier, where we have seen growers getting most comfortable growing vertically. Anders mentions, “ In the early days of legalization, we understood less about indoor cultivation facility design than we do today. Often, veg rooms were undersized for a facility, creating a significant bottleneck and leaving flower rooms unpopulated for longer than needed.” The natural solution is to take advantage of the cubic footage of your commercial building and grow vertically. “Common best practice now when sizing your total veg canopy for a facility is to allocate between 20% to 30% of your total flowering canopy footprint for veg space.”
“A well-designed and engineered facility can produce, in some cases, up to two to three the amount of yield than of a poorly designed facility of the same size,” Michael states. Pipp has installed more than 2,500 vertically stacked grow rooms over the past six years, and some of the best insights and things we’ve learned are on the design of a vertically stacked flower room. Two-tiered flower rooms are more common than three-tiered flower rooms. However, three-tiers are getting increasingly popular due to the fixed cost absorption of producing more products per square foot. Two versus three tiers also really depend on the constraints of your building, your ceiling height, license type, and how much flowering canopy you need for your business plan.
For labor and harvesting efficiency and climate control reasons, we found that a good sweet spot for the overall size of a flower room is between 2,000-3,000 canopy square feet, regardless of that being two or three tiers. We recommend row lengths of 32-40′ or shorter for good airflow within the room. The longer the rows, the more likely microclimates are to form. Tip: “When it comes to operating a multi-tier flower room, transitioning the plants to flower and timing the stretch is everything. Before moving the plant from the veg room to the flower room, it is best to set the climate to VPD to match the VPD conditions in your veg room to limit the stress.” – Anders Peterson.
Pipp recognized early on that proper airflow is one of the most significant limiting factors to success within a multi-tier grow room. To prevent or reduce microclimates within the space and create a consistent environment, in-rack airflow systems are necessary. Del mentions, “The goal is the have the same environment throughout the room. Whether it’s the first tier or the fourth tier, we’re trying to make it as consistent as possible.”
Vertical Air Solutions, VAS, was developed to be a low-profile in-rack air circulation system that seamlessly integrates with the lighting and the racking to ensure that it is a smaller form factor and takes up as little space as possible. Anders mentions, “Often the most limiting factor to producing quality and good yields of a multi-tier flower room is an improperly designed mechanical system.” What we find to be successful is supplying the air in the front main aisle, letting the in-rack airflow fans capture the dehumidified, conditioned air, and pushing it down the length of the rows. Ideally, these rows are less than 32 to 40 feet to limit air travel distance. And then, the air is returned to the back wall at multiple elevations and completely recirculates along this path. Michael states, “Your in-rack air circulation is only as good as the HVAC system design.”
For many, the design and operation of a drying room can be challenging and, if not done correctly, can result in a significant bottleneck and degradation of product quality. It balances science, traditional methods, and “respect for the plant.” From a design standpoint, you typically see an undersized drying room and undersized HVAC and dehumidification capacities. Cultivators can grow a beautiful final product that is high quality, yet in a matter of days, it starts degrading from an underperforming dry/cure process.
There are a wide variety of options and solutions for each grower’s unique approach to drying. Our mobile carts help assist with room-to-room mobility; transferring the plants onto a cart and then into the dry room is a significant advantage. Something to keep in mind when using our dry carts is paying attention to door heights. Choosing door heights and widths that can accommodate the movement of all equipment throughout your facility to avoid issues during startup and operation is essential.
Tip: “As a best practice, we encourage cultivators to have minimal downtime between harvests—ideally, a next-day room reset. We define a next-day room reset as harvesting all the plants in one day or shift in that flowering room or zone, cleaning and sanitizing that room ideally the same day or the very first thing the next morning. Then you are resetting and repopulating that flower room the day after harvest. Each day that you are not flowering has significant ramifications on potential revenue loss.” – Michael Williamson.
We also provide complete mobile units in a variety of options. Light-duty rivet units are a robust and solid solution but a bit lighter than some bulk racks. Bulk racks for the dry room come with the ability to use the ELEVATE® Platform System, having access to the higher levels. Different options include hang bars, flat wire grids, or cantilever finger bars. The cantilever finger bars provide flexibility and easy access for hanging plants in the dry room.
Why You Would Choose One Process Versus Another
Some growers prefer to hang the entire plant; others like to break a plant down into individual branches at harvest. Anders mentions, “It’s best to size a dry room to fit a whole harvest from a single flower room at a time.” Most growers today prefer the single load-in strategy of one flower room into one right-sized dry room. Another best practice for a dry room is installing a timer for your overhead lights to help limit photo-oxidation of your product during drying. Install an auto closer on all doors in your dry room to keep the doors shut as often as possible to prevent uneven drying and loss of capacity from your HVAC system. “In summary, each plant stage, including harvesting and the strategies you deploy, can either have a beneficial or non-beneficial impact on the quality of your final product. Tuning your mindset to consider and evaluate not just what you do to plants, but why and how it positively or negatively impacts the end user is the ultimate goal.” – Michael Williamson.