How Much Veg Space Do You Really Need at a Commercial Cannabis Grow?

Updated January 2025

Successful commercial cannabis cultivation is all about efficient management of the growth cycle. Like everything else in this industry, that depends on your production goals and market demand. While a lot of attention is on the harvest, one of the biggest determining factors in the best grow room design plans is vegetative growth, believe it or not.

The flowering phase of cannabis cultivation can feel like the time where all the magic happens—feminized and autoflower seeds were both developed to finesse this crucial part of the cannabis growth cycle. But as important as the flowering phase is for maximizing cannabinoid and terpene content, as well as flavors and other genetic expressions, it’s vegetative growth that really shapes a facility's design, operational workflow, and compliance with state regulations.

Regulatory and Methodology Considerations

Your cultivation methodology and local regulations significantly impact the required veg space. For instance, managing a single generation of autoflower plants to supply multiple flowering rooms on a tightly timed veg cycle necessitates a different setup compared to handling several rooms with staggered plant generations. 

State-imposed plant count limits, such as those for cannabis microbusiness license categories, further dictate veg room sizing and plant turnover rates. In states with strict plant count limits, cultivators often extend the vegetative phase to maximize yield per plant, resulting in larger plants and consequently, they need more veg space. Conversely, in regions without such limitations, growers may opt for shorter veg cycles with smaller plants, allowing for higher turnover and potentially reduced veg space requirements.

Strategic Veg Room Placement in Commercial Cannabis Grows

Efficient facility design begins with the strategic placement of veg rooms. Ideally, these rooms should separately house mother plants, clones and tissue culture to prevent issues with bud rot, hop latent viroid and the spread of other pathogens, as well as to streamline operations. If space is limited, vertical grow facilities can maximize canopy area—although racking with set heights means growers need to stick to the top strains for multi-tiered grows. Additionally, it's advisable not to exceed three tiers to maintain safety and operational efficiency. 

Whatever the setup, proper segregation of veg areas from main traffic zones minimizes contamination risks and enhances workflow efficiency.

Lighting Considerations for Veg Rooms

Selecting appropriate lighting is vital for healthy vegetative growth. Typically, veg rooms require about 20% of the light wattage used in flowering rooms, but this can vary based on factors like fixture type and cultivation methods. 

LED grow lights are often preferred in veg rooms over more traditional high-intensity discharge (HID) lights for their energy efficiency and lower heat output, and they also facilitate multi-tiered setups. The choice between high-pressure sodium (HPS), ceramic metal halide (CMH), and LED fixtures should align with your specific cultivation goals and facility design.

Consistency in Room Sizing

Maintaining uniformity in the size of flowering rooms ensures a steady flow of biomass through your production process, simplifying management and optimizing output. The number of veg rooms needed depends on your specific cultivation methodology and plant count. Consistent room sizes facilitate predictable harvest schedules and efficient resource allocation.

Maximizing Plant Density

The number of plants you can cultivate in a given space, such as a 10x10 room, depends on your growing techniques. Utilizing approximately 70% of the floor space for the canopy allows for efficient plant arrangement. Implementing tiered growing systems can further enhance production capacity. 

Separating Veg and Flowering Phases

While it's possible to veg and flower plants in the same room, it's not recommended for commercial operations. Veg and flowering stages have distinct environmental requirements—especially for photoperiod plants—and combining them can lead to suboptimal conditions for both growth phases. 

Dedicated spaces for each stage of the cannabis growth cycle allow for tailored environmental control and resource allocation, promoting plant health and better yields. By carefully considering plant development, you can design a cultivation facility that maximizes efficiency, ensures compliance, and produces high-quality cannabis. 

Want to talk more about optimizing yield and quality of harvest, the best cannabis facility design for your goals, equipment and materials selections and cannabis genetics? Contact Next Big Crop today.