Indoor vs. Greenhouse Cannabis Cultivation: An Industry Veteran’s Perspective

With years of hands-on experience in the cannabis industry, I’ve seen firsthand the evolution of cannabis cultivation. One of the most consistent questions I get asked is, what are fundamental differences between growing cannabis indoors and in a greenhouse?

Both methods have their unique advantages and challenges, and making the right choice really boils down to understanding your goals, your resources, your ability, and your environment. I will share some insights from what I’ve seen firsthand.

The Core Cost Differences: Setup and Operation

When planning a cultivation facility, cost is always a primary consideration. There are a lot of similarities in what you’ll need to pay for, but the cost structure for indoor versus greenhouse can be vastly different.

Indoor facilities generally come with a higher upfront and typically ongoing cost. Why? Because you’re building a fully sealed, fully controlled environment from the ground up. This means you should be prepared to make heavy investments in things like lighting, HVAC, electrical infrastructure, and increasingly, automation. We’re talking about structures that are usually framed steel buildings with opaque, heavily insulated walls – often in retrofitted warehouses or purpose-built facilities.

Greenhouses on the other hand, are typically going to have a lower construction cost per square foot. The main reason is that greenhouses get to leverage more natural elements, especially sunlight and fresh air, which significantly helps to reduce energy bills and ongoing operational expenses. However, they still require different levels of environmental control, largely dependent on your location. But generally, if they’re optimized and the climate permits, greenhouses are more cost-efficient in the long term.

Building Design and Environmental Control: My Approach

The design really dictates your control.

With indoor facilities, there’s no natural light. This means we’re creating 100% of the light the plant needs. We also typically divide indoor spaces into smaller rooms, allowing for slightly more control over individual, smaller batches. More rooms do mean more equipment, which adds to the expense, but you gain increased granular control. Things like vapor barriers, moisture control, and pest prevention are managed differently in this sealed environment. We also must account for noise and smell reduction, which is a bit easier to contain in a fully enclosed building.

Greenhouses are designed to maximize natural light. Their structures are typically made of glass or polycarbonate with aluminum or steel framing. The focus is on optimizing solar gain based on geographical alignment. The biggest challenge here is climate exposure. You must design everything from below-freezing temperatures and snow load to 120-degree heat, dry conditions, and high light levels which can more rapidly degrade materials. Zoning and site considerations also come into play; sometimes agricultural zoning offers different incentives for greenhouses than they do for indoor facilities. And sometimes, you might even opt for a natural foundation instead of concrete.

The crucial difference for me is this: in an indoor facility, we are manufacturing the environment. In a greenhouse, we are controlling what the natural environment is doing and changing throughout the year. This means greenhouses absolutely require things like blackout systems and shade curtains to manipulate the plant’s photoperiod.

Quality and Consistency: Where Each Shines

This is a big one for growers, especially for those aiming for premium products.

Generally, I’d say indoor grows, on average, offer a slightly more consistent product and higher quality results. This is almost entirely due to the sheer level of control and consistency you can create. Especially in the premium flower category, where buyers are looking for very specific attributes, the ability to control every aspect—lighting intensity, spectrum, humidity, temperature, pests, pathogens, pruning, and upkeep—leads to more reliable outputs. You have to achieve a minimum standard for temperature and humidity in an indoor room, or “all hell breaks loose,” as I like to say.

Greenhouses can absolutely produce top-shelf cannabis with unique attributes. However, achieving that often requires a higher level of sophistication and equipment to provide environmental stability. You’re constantly relying on your equipment to react quickly to natural fluctuations in light and temperature. When you have a lot more plants in a space, like in a greenhouse, it can also become harder to identify problems early. That said, some of the most highly sophisticated greenhouses can certainly compete with the highest level of indoor quality.

Lighting Strategies: Manufacturing vs. Complementing

Plants use light the same way, regardless of where they’re grown. How that light is delivered, however, is very different.

Indoors, we have the highest level of control. We dictate exactly how much light, what intensity, and what spectrum the plants receive, for how long. The Daily Light Integral (DLI) is more of a retrospective calculation here; what really matters is the consistent PPFD (Photosynthetic Photon Flux Density) over the photoperiod. More light generally equals more production, in a roughly one-to-one ratio up to a certain point.

In a greenhouse setting, our goal is to complement the natural light pattern. We supplement the light to ensure the plants receive their total required amount, adapting throughout the year based on natural conditions. This requires sensors feeding into control systems that tell us when there’s a light deficit and to increase light intensity. While sunlight has a magical, deeply penetrative quality that artificial lights don’t quite replicate, we can use supplemental lighting to average out DLI inconsistencies throughout the day.

Spectrum gets trickier in a greenhouse. We know that too much absolute red light can lead to adverse results like photobleaching on flowers. The sun has a certain percentage of red; if we’re adding to that, we need to be careful not to exceed the plant’s natural tolerance to red light. An 80% red spectrum fixture (R8) might be highly efficacious, meaning it uses less wattage, but it also puts you in a “danger zone” for having too much red. If you’re not careful with supplemental levels of red light combined with the sun you could be setting yourself up for adverse reactions. Indoors, we have complete control over the spectrum we deliver.

Pest and Diseases: Common Battles, Different Fronts

Regardless of location, technically, you’re always fighting the same battles because we’re working with the same plant, same pests, same diseases. However, the exposure that growers are managing differs.

Greenhouses are more exposed to outside air and elements due to a less secured perimeter. Many rely on active and passive cooling systems that bring in outdoor air, which can introduce other issues relating to the atmosphere. So, greenhouses generally have slightly higher potential for pests and pathogens.

That being said, a massive factor for both indoor and greenhouse is human interaction. We are the biggest mode of transportation for pests and pathogens. My advice is always to have the most stringent of protocols: high levels of PPE, separate inside/outside clothes, changing rooms, foot washing stations, and not sharing equipment between different areas. While a greenhouse might have air intake that needs scrubbing, the overall responsibility for pest management and prevention is similar for both. The challenge in large greenhouses, however, is that it can be harder to spot problems early across hundreds or thousands of plants compared to smaller, more compartmentalized, indoor rooms.

Regulatory and Compliance: Location is Everything

This is where your specific location becomes paramount. There are many differences, depending on the state, county, city, and even local zoning ordinances.

First, you need to find out where you can even build. Some places simply make it impossible to build a greenhouse or an indoor facility. Then there are more specific rules or regulations:

• Odor Mitigation: Indoor facilities, being tighter and more controlled, generally find it easier to achieve required odor mitigation levels. Greenhouses, relying on outdoor air, might need more robust systems.
• Security: Indoor facilities, often in steel or brick buildings, are usually easier to secure with barbed wire, cameras, and security teams. Greenhouses are more exposed, relying on sturdy fences and perimeter cameras across open spaces.
• Agricultural Regulations: Especially in greenhouses, you’ll face agricultural regulations concerning runoff, discharge, VOCs, cleaning chemicals, and even your SOPs for pesticides and pathogen responses.

It’s not just about getting an electrical permit or a cultivation license; there are many layers of regulatory hurdles people should be prepared for.

Yields: It’s About the Photons

If you can control a greenhouse to deliver a consistent target PPFD throughout the year, similar to an indoor setup, then the rule of thumb should be the same: the amount of photons you deliver directly correlates to your yield.

However, the sun is a different light source. It has a unique penetrative quality that even the best LEDs can’t quite replicate. So, while the quantity of photons might be the same, the spectrum that’s being delivered, how those photons penetrate the canopy, and the plant morphology can be subtly different. You might find you have to manicure plants differently under full sun supplemented by LEDs compared to full LED or HPS lighting indoors.

Staffing: Scale Dictates Structure

There are many similarities in how to staff a facility because the tasks are largely the same. Cannabis goes through the same cycles weather they’re grown indoors or under glass. The big differentiator is scale.

In an indoor facility, you might be harvesting 50-pound batches every week. Your harvest, cleanup, and room reset teams might work on a very consistent, weekly schedule. Often, indoor teams “cycle around the projects,” meaning the planting team also helps with harvest, hanging, and bucking. Some indoor facilities even require 24-hour employees, perhaps running rooms at night for energy purposes. Multi-level facilities, while more complex to build, can offer personnel efficiency because employees don’t have to travel as far to do their work.

In a greenhouse, especially a large one, you might harvest 1,000 pounds in a batch, but perhaps only once a month. This means your personnel needs and scheduling will be different. You might have a specific harvest crew that comes in periodically, and then a dedicated “plant team” that manages cultivation for the rest of the cycle. Larger greenhouses often have more staff, treating operations a bit more like commercial agriculture.

My Advice: Choosing Your Path (Especially for New Growers)

If you’re a new grower in a “magical land” where zoning isn’t an issue and you’re well-funded, my first piece of advice is to hire an experienced grower. They’ll help you navigate some hard decisions, pulling from their previous experience.

But if I had to nudge you: growing indoors is generally more forgiving and easier for an inexperienced grower. The level of control makes it simpler. Is your temperature too high? Put in more AC. Humidity too high? Get a dehumidifier. These are straightforward, cookie-cutter solutions. An indoor grower can get pre-made soil, push play, and as long as their equipment works and they remember to water, it can be quite easy. Grow tents, in particular, have revolutionized the home grower game because they make growing so accessible.

Greenhouses require more knowledge and know-how. You need to understand the complex relationships between the outside and inside environments and how to manipulate them, often with less equipment.

Finally, geography can have a massive impact. In places like Miami, you’re constantly battling high humidity, high heat, and pest pressure. To produce high-quality cannabis in a Miami greenhouse, you’d need extremely tight controls, possibly equivalent to an indoor facility. If you’re okay with mid-level products and accept some losses (like botrytis), you might get by with less tech. Conversely, in places like Saskatoon, you’re focused on keeping the greenhouse warm and providing enough light during short winter days.

Conclusion: Making the Right Choice for Your Grow

In my years in the industry, I’ve seen successful operations thrive in both indoor and greenhouse settings. There’s no single “best” method; the ideal choice is always context-dependent.

Indoor cultivation offers unparalleled control, leading to superior consistency and quality, especially for premium flower. It’s often the more forgiving path for newer growers due to its predictable environment. However, this precision comes at a higher capital and operational cost.

Greenhouse cultivation leverages natural resources for greater cost-efficiency, particularly in favorable climates. It offers a pathway to high-volume production but demands a more sophisticated understanding of environmental dynamics and a proactive approach to managing external influences like climate and pests. While capable of producing top-tier products, achieving this consistency often requires significant investment in advanced controls.

Ultimately, before breaking ground, ask yourself: What type of product am I aiming for? What market am I serving? What are the specific environmental conditions of my location? And how much control do I need versus how much am I willing to invest to achieve that control? Answering these questions truthfully will guide you to the cultivation method that best suits your brand, your budget, and your long-term vision.

To learn more about what could work best for your grow, reach out and speak to one of our horticulture specialists. They can assist you in analyzing your environment and goals.

Casey Rivero

Cannabis Solutions Architect

Casey Rivero is a seasoned cannabis industry professional with over 20 years of experience, known for his work in developing efficient and sustainable cultivation models with established companies across multiple states. Casey combines a deep understanding of business drivers with expertise in facility design, operational efficiency, and commercial solutions. His hands-on approach to business planning and facility implementation has made him an influential figure in the industry, continuously advancing new methodologies and scientific insights. With an extensive background in botany and horticulture, Casey has collaborated with leading manufacturers in lighting, nutrients, soil, software, and HVAC systems, designing studies to enhance product performance and optimize cultivation outcomes. Passionate about education, Casey regularly leads workshops and presents at conferences worldwide.