You might not think of the vegetative spacing in a cannabis cultivation facility as a revenue stream (unless you sell clones or tissue Culture) but these spaces can impact the performance of EVERY flower run. With that in mind, it’s important to note some factors that influence the successful operation of a vegetative space.

Designing or optimizing a cannabis vegetative space is more intricate than it appears. With varying standard operating procedures (SOPs), cultivation media, and crop management techniques, defining guaranteed success is challenging. What constitutes success in this context? Is it the ability to produce enough clones to supply flower rooms, harden off vegetative plants for greenhouse or outdoor growth, maintain healthy mother stock, or run a cloning business? Each goal requires different metrics and considerations.

Sadly the vegetative cultivation space usually draws a short start on funding. It’s not sexy, those rooms don’t produce flowers and as a result, they often get repurposed HVACD equipment, larger tolerances for setpoint variation, more lax management, and they are assigned fewer performance metrics to show their influence on business health.

At scale, the importance of a healthy veg is profound. Slow-rooting clones require more labor and are prime targets for pathogens and a low rooting success rate means you will have to put some of your not-so-best horses in the race. If hardening off takes too long you limit the number of turns you can have per year and the lack of root development will show in a reduction in yield. And if you can’t keep your moms happy you risk infecting the whole facility, losing precious genetics, and reducing the performance of every batch.

Traditional rockwool/coco, Aeroponic, Cloning machines, Soil for mom, Specific fertigation, appropriate defoliation, various IPM applications, plant movement from phase to phase… There are a lot of moving parts in the veg space.

Veg has its own symphony.

Moms go from being the lead singers to conductors. And if they get sick they die…and so do all of their offspring. I think this is one of the best cases for tissue culture to preserve genetics for future access in case you are unable to manage mom’s health you can “start fresh”.

So what are some of the most important considerations to make sure your band is performing as well as possible?

How much space do you need?

1. For Mother Plants:

You will need to consider how much room you need for mother plants by factoring in plant height, access requirements, airflow needs,  the mother plant life cycle, and how fast your mothers produce cuttable material. 

Tier spacing: Due to the growth style and space needed mother plants are often grown on single-tier racks but multitier is also possible with tier spacing of 6ft or more.

VPD: 0.8 helps mothers produce more shoots, maintain root growth, and consistently support the cloning need for the facility

Mobile Aisle: A 36-inch mobile aisle is the minimum width from a compliance perspective and works well for mother plants. If cutting work is to be done in the aisle you may want to consider a larger mobile aisle to increase the working space.

2. For Cloning:

Traditionally wire rolling racks have been used in clone rooms but there are superior options from a workflow and room utilization perspective as you scale your facility. 4ft wide trays can be used with wire decking but 5ft wide tables fit more flats and provide the highest cutting per sq inch utilization. Typical clone trays are 10inx20in. That means on a 4ft wide tray you can fit two across and have an 8inch gap of wasted space. With a 5ft wide tray, you fit three wide and increase total capacity significantly.

Tier spacing:  Spacing needed in cloning is lower than other spaces around 2 to 3ft, which allows for 5 or more tiers per row depending on ceiling height.

VPD: 0.5ish is a popular choice to stimulate root growth. Most cultivators dome their clones but VPD and airflow are still important in order to homogenize leaf temperature and stimulate rooting.

Mobile Aisle: A 36-inch minimum is very functional in this space but a 40-inch mobile aisle would allow for double-wide access decking and a larger platform for load-in which increases efficiency by reducing labor costs.

3. For Vegetative Growth:

How much space do you need: 25-30% of your flowering canopy sf. The important thing to remember is the load in schedule and making sure plants are ready to head to the flower room on schedule. But it’s also important to have enough plants that you can cull the weakest ones. A popular kill rate target is 10%.

Tier spacing:   Spacing from 3ft -5ft depending on lighting and integrated airflow. The small plant height and high planting density of this transition period make it a good option for 2, 3, or even more tiers depending on need.

VPD: 0.8-1.0 is a popular range that allows you to gradually harden off rooted plants and prepare them for the environmental conditions they will enter in the flower space

Mobile Aisle: The hardening-off period as plants prepare to enter flower rooms can often need the most management. They might need defol, root analysis, topping and morphology management, and IPM applications…these tasks can benefit from a mobile aisle minimum of 40 inches which allows for wider access decking to complete these tasks most effectively and efficiently.

VPD debates:

VPD setpoints are always up for debate with specific genetics responding to different setpoints. More important than having a target VPD in mind is controlling the humidity and airflow in order to effectively maintain conditions optimal for root, shooting, or hardening off/ rapid growth. Test, adjust, and align are the best ways to stay on target as vegetative plants are growing rapidly.

The nuanced setpoint differences between Mother plants, clones, and vegetative hardening are one reason cultivators have historically built separate rooms for these stages. Today with a good understanding of HVACD and airflow cultivators have begun creating shared rooms that unify the HVACD system to serve a singular space shared by mothers, clones, and vegetative transition. With EC fans and integrated airflow solutions like AirGlide or Updraft cultivators can have a row of mother plants, next two a three-tier veg, next to a 5 tier clone row all on the same track. This increases labor efficiency and lessens plant travel while increasing success rates. Being strategic with supply and return locations, dehumidifiers and integrated airflow allows the cultivator to control climate zones in the room creating ideal environments for all plants at every stage of vegetative growth.

Eliminating The Veg space altogether? How does this pan out?

While this might sound risky you now need an outside source for genetics. There are companies that produce clones for sale at a large scale at the commercial level that can provide regular delivery of clean genetics that can be loaded into flower rooms and flipped quickly without the need for management of vegetative spaces. While there are risks associated with accepting plants delivered to your facility this option may also empower facilities to add additional flower rooms to their facility. The idea of eliminating veg might be jarring but you also eliminate the labor for veg management, specific veg goods, various SOPs, potential contamination zones, and the list goes on. While you are now dependent on a genetics supplier your facility can now focus, specialize, and refine the processes needed to produce high-grade flowers, consistently and as efficiently as possible.

Tissue culture is another option for outside sourcing but will require a small space to “wake them up” before moving them into the flower space to veg in place shortly before the flip.

Either way eliminating the veg space would still require a specific quarantine room for receiving, inventory of new plants, and assessment/treatment before entering the flower rooms.

Quarantine location: Quarantine rooms in facilities make me wonder what solitary confinement is like in maximum security prisons. I imagine it’s poorly lit, there is no bed, the food is always a little off and you are dying as much as you are living. Often time quarantine is a punishment but it could be a small retreat.

Imagine a small room with 1-2 rows, and three tiers. 

The bottom tier is 6.5ft with appropriately mounted lighting to allow for mothers to fill the space Dedicated HVACD, pampering with foliar applications, easy-to-access, and load in and out and dedicated in-rack airflow in the form of air glide allow for more than recovery and prepare them to reenter production zones.

The second tier with 4ft tier spacing to allow for vegetative plants to receive appropriate PPFD and managed airflow provided by the Updraft solution from Grow Glide. This space empowers analysis, morphology control, easy IPM application, and rapid growth for this stage.

The Top tier might only need another 30 inches, with wire decking in order to slide in trays of rooted, unrooted, or otherwise freshly acquired small plants. This tier can utilize EC fans from Grow Glide to move air across the top of the domes, pulling stale air and expediting the rooting of the entire row.

This kind of room is not one of suffering but one of flourishing. By investing in a quality quarantine room and designing efficiently plants will be bound back quicker, transition faster, and require less labor to prepare for future phases of growth.

Vegetative rooms are nuanced but require some of the same infrastructure as the flower rooms.

1. Environmental control:

Temperature, humidity, Air movement, and VPD must be controlled in order for plants to perform their best. Undetsding differing needs of vegetative plants at different stages allows justification for the purchase of mechanical systems, fans, and retrofit expenditures to achieve future success.

2. Lighting:

Moms, Vegetative hardening, and clone spaces require differing lighting applications to optimize. Understanding the light output, mounting height, defoliation practices and goals for each stage informs the best lighting choice and empowers the most efficient plant production.

Space and layout:

Making sure that your vegetative space is as productive as possible without becoming an uncontrollable jungle has to do with your racking layout and SOPs. Making sure that you have the appropriate plant spacing and aisle spacing ensures consistent airflow, prevents pathogen outbreaks, and encourages better completion of SOPs.

3. Nutrient and Media management:

It’s important to make sure mother plants get what they need to maintain health over the long haul and produce healthy cuttings as quickly as possible, while fast-growing veg plants require different nutrition and cloning requires a different need. In addition, it’s important to understand the impact of your media choices. You might have mother plants in the soil, clones in rock wool, and veg/flower in coco. Understating how differential media or even the same media of different sizes respond at transplant can help refine SOPs and streamline the vegetative growth transitions.

4. Pest and Pathogen treatment:

The vegetative stage is a great opportunity to apply IPM strategies you might not want to in Flower. Not the application of banned substances but rather foliar applications of oils (that you might not want to stick to terps in flower) or sulfur (that will negatively impact flavor when sprayed on your flower). Knowing what to apply, when, and at what dilution in the vegetative stage will impact future plant health as well as the efficacy and options of what you can spray in the flowering stage.

5. Automation, controls, and data collection:

Just like the production of grade a flower the vegetative space needs consistency which is often achieved through automation. Automation also allows for precise measurement and fine-tuning of the system you have built through the analysis of the data collected. Data can also influence SOPs, like when and how you defol in order to make the biggest impact on plant health or yields.

Conclusion:

Designing efficient cannabis vegetative rooms involves balancing various factors, from environmental control and lighting to space layout and nutrient management. By carefully considering these elements, growers can create spaces that optimize plant health and productivity, ensuring success in their cultivation endeavors.