Wondering how a cannabis greenhouse works? Learn more about SunMed's state-of-the-art Dutch-style greenhouse.

Exploring a Cannabis Greenhouse

Ever wondered about the inner workings of a cannabis greenhouse? Just like any other plant, cannabis requires certain conditions to thrive. A greenhouse provides the perfect environment, harnessing the power of nature while protecting the plants from harmful elements. 

At SunMed, we see the greenhouse not just as a structure, but as an eco-friendly cultivation method that marries the best aspects of indoor and outdoor growing while minimizing their disadvantages. The result is a sustainable, efficient, and effective way to produce high-quality cannabis, and that's why we prefer it. We’ll explore this fascinating world through SunMed’s state-of-the-art, Dutch-style greenhouse. Along the way, we’ll also provide tips for home growers considering their own greenhouse project.

The Anatomy of a Cannabis Greenhouse

The success of a cannabis greenhouse hinges on several integral components working together harmoniously. From the architecture to the irrigation system, each element plays a critical role in creating the ideal conditions for cannabis growth.

Anatomy of a Cannabis Greenhouse 

Greenhouse Glass 

Its namesake and its most characteristic element, the specialized glass or plastic used in a greenhouse allows maximum sunlight penetration. More sunlight equals more energy for photosynthesis, which leads to robust, healthy plants. In many cases, the structure is further fortified to ensure effective heat and CO₂ retention.

At SunMed Growers, we use double-paned glass for our greenhouse. Double-pane is more energy efficient as it traps heat, reducing overall energy consumption without compromising light levels. However, double-pane is the pricier option, and single-pane is certainly viable for smaller greenhouses. As we discuss more below, DIY greenhouses can make use of even more affordable materials and still provide protection and sunlight for small operations.

Greenhouse Architecture

There are a wide variety of greenhouse styles to choose from depending on your climate, weather patterns, planned crop size, and budget. We’ll cover two important categories here, one more suitable for commercial growing and another that’s a better fit for small growers. 

Dutch Greenhouses

As its name suggests, this style of greenhouse originated in the Netherlands, where light is low and much of the land is near sea-level. They are designed not only to capture as much sunlight as possible, but also to retain CO₂ and distribute it more efficiently, since it plays an important role in cannabis growth and yield.

Dutch greenhouses are particularly ideal for large-scale growers in climates where capturing the maximum amount of sunlight is a priority. For sunnier climates, other considerations may take precedence. For instance, in climates that receive a lot of sunlight but are prone to natural disasters such as hurricanes, growers may want to prioritize structure and stability. 

You might consider a Dutch greenhouse if you’re looking for:

  • Large-scale or commercial cultivation

  • Maximum light levels and retention

  • Superior climate control

SunMed Growers Greenhouse Aerial View

Low and High Tunnel Greenhouses

Low tunnel greenhouses, also known as row covers or hoop houses, are simple, cost-effective structures that provide a controlled environment for plants. They feature long, tunnel-like roofs created by a metal or plastic frame that can be covered with a layer of plastic or fabric, making them ideal for small and independent growlers. They’re simple, easy to build structures you could put up in your own backyard. Consider a low-tunnel greenhouse if you’re looking for:

  • Additional safeguards for outdoor growing

  • Early planting

  • Small-scale cultivation

  • Minimal investment

High tunnel greenhouses are more substantial versions of low tunnels. They are generally larger and made of sturdier metal and plastic materials. They provide similar benefits as low tunnel greenhouses but with more stability and space. High tunnel greenhouses are good for:

  • Enhanced climate control

  • Medium-to-large scale cultivation

  • Moderate investment

Prefabricated Gables and Other Structures

The world of greenhouse architecture is vast and diverse. If you have a little money to spend, and would like to avoid a DIY build, there are lots of prefabricated options available. These can range anywhere from lean-tos to gables to geodesic domes and much more. Prefabricated greenhouses are available at many home improvement retailers. 

Greenhouse Flooring

The flooring in a commercial cannabis greenhouse serves a practical and hygienic purpose. It's often made from permeable materials that allow water to drain away, preventing water logging and associated root diseases. The flooring is also easy to clean, which helps ensure a hygienic environment for cannabis cultivation.

If you’re designing a greenhouse for personal use, however, it’s okay if you don’t install any flooring at all. The ground itself makes a perfectly suitable base for most small growers. However, you can choose from a wide range of floors to promote drainage, including materials such as mulch, concrete, gravel, or permeable plastic. 

Greenhouse Irrigation

In a commercial cannabis greenhouse, the irrigation system is typically automated, providing the precise amount of water required by the plants. By controlling water delivery, growers can prevent overwatering and underwatering, two common issues that can hinder cannabis growth and yield. 

Small growers may choose not to install irrigation, but to water by hand. If you do, make sure to leave plenty of space in the walkway of your greenhouse so you can reach all of your plants with your hose. Keep in mind that plants grown in pots generally do not require as much water as those grown in the ground, but also that water will evaporate more quickly outside than it does indoors. If you find that you’re having trouble with standing water inside your greenhouse, consider one of the flooring options listed above. 

Greenhouse Irrigation

Supplemental LED Lighting 

While a greenhouse utilizes natural sunlight, commercial greenhouses often incorporate supplemental LED lighting to ensure consistent light levels year-round or to accommodate plants in different stages of their life cycle. This is especially important during shorter winter days in states like Maryland. SunMed partners with Fluence to provide our plants with optimal light conditions for growth and flowering.

Another consideration, especially for commercial growers, is light intensity. Our partners at Fluence are experts in the science of light intensity, and they’ve done their own extensive research on optimal intensity levels for growing cannabis. If you’re supplementing with your own lighting and aiming for higher yield, light intensity is definitely an important consideration since both too little and too much light can negatively affect your plants’ growth.

But if you just want to grow healthy plants without too much fuss, then you mainly need to be aware of lighting at different stages. In the vegetative stage, many growers will provide up to 18 hours of light, whereas 12 hours is sufficient for the flowering stage (keep in mind that darkness is also important to plant health, so more can often be less).

Automation (Tables & Elevators)

Automated systems like movable tables and elevators allow for efficient use of space and easy access to plants for maintenance and harvesting. These systems enhance operational efficiency and can contribute to improved plant health and yield.

At SunMed, our plants are cultivated on a rolling table, and we utilize industrial robotics to move these tables through our elevator system for indexing and processing. It’s definitely not your mom’s greenhouse! Watch a virtual tour of our greenhouse here

Automation

Botanical Considerations

Finally, perhaps the most important consideration for greenhouse growers is the seeds you choose to cultivate. Cannabis genetics plays a direct role in THC levels, color, and the effects of the plant. These key elements can’t be controlled just through horticultural skill alone. Therefore, when choosing seeds, consider the following:

  • Indica vs. Sativa: Indica strains are typically more relaxing, while Sativa strains are more energizing. Hybrids offer a mix of both.

  • Potency: Consider the THC and CBD levels according to your needs and preferences.

  • Color and Appearance: Mature seeds are often dark brown with a glossy finish. Avoid pale or green seeds.

  • Size and Shape: Opt for larger, symmetrical seeds.

  • Reputation of the Supplier: Purchase from reputable seed banks or suppliers with positive reviews and proven track records.

Cannabis Greenhouse FAQs

If you’re curious about commercial growing, or interested in starting your own greenhouse, you may still have questions about how they work. Here are a few of the most common. 

Does Cannabis Grow Well in a Greenhouse?

Cannabis does more than just grow well in a greenhouse; it thrives. Greenhouses provide the perfect blend of natural sunlight, climate control, and protection from external elements, creating an environment that allows cannabis plants to flourish.

What Are the Advantages of Cultivation in a Cannabis Greenhouse?

The utilization of natural sunlight is a significant advantage of greenhouses. Sunlight is a highly effective light source for plant growth, and it's free! It promotes robust growth and helps develop rich, complex cannabinoid profiles in the plants. While indoor growing relies heavily on artificial lighting, a greenhouse's ability to harness natural sunlight makes it more energy-efficient and environmentally friendly.

For commercial growers like us, greenhouse cultivation helps us commit to sustainable farming practices. Indoor growing has a notoriously high carbon footprint. By harnessing the power of the sun and reducing the need for artificial lighting, we're able to reduce our carbon footprint and produce our high-quality cannabis in a more environmentally responsible manner.

The main drawback to greenhouse growing for most individual or small-time growers, though, is the upfront cost of investment and ongoing maintenance. These are important considerations, but here are some reasons why a personal greenhouse might well be worth the investment:

  • Longer growing season thanks to protection from the elements

  • Increased security for your plants and privacy for you

  • More CO₂ delivery to the plant, which helps with growth and production

  • Better environmental protection and control, especially for plants in the vegetative stage

How Much Does It Cost to Build a Cannabis Greenhouse?

If you build and design the greenhouse on your own, a simple structure can cost as little as a few hundred dollars. Prefabricated greenhouses can also be relatively cheap. A small hobby greenhouse can range anywhere between $500 to $5,000, while a large, commercial-quality structure can start around $10,000-$20,000 or more. 

The choice of materials can significantly impact the cost. The cheapest options are thin plastic or even fabric as an alternative to glass. Polycarbonate or polyethylene coverings are also generally more affordable than glass, while the type of framing material (e.g., aluminum, galvanized steel, or wood) can affect the price as well. High-quality, durable materials will come at a premium but may save on maintenance and repair costs down the road.

Finally, while it isn’t necessary, you may choose to invest in more advanced systems such as irrigation, heating and cooling, supplemental lighting, and foundations and flooring. All of these add substantial cost, but also value, security, and environmental control.

How to Decide Between a Cannabis Greenhouse and Indoor Growing

Indoor growing offers the highest level of control over all environmental variables impacting cannabis cultivation, from light exposure to temperature, humidity, and CO₂ levels. This level of control can result in high-quality cannabis, but it also comes with a significant energy cost due to the reliance on artificial lighting and climate control systems.

Here are some questions to ask when deciding between a greenhouse and indoor grow:

  • Would you prefer to grow cannabis outdoors, but have concerns about climate or pests? 

  • How much of a priority is the security of your property?

  • Do you have a suitable indoor space for growing in which it will be possible to set up lighting and irrigation? 

  • Are there climate considerations in your area that would require a costly investment in greenhouse materials? 

Can you Grow Cannabis in a Greenhouse Year-Round?

With the right set up, it’s possible to grow cannabis in a greenhouse year-round. Provided that you’re able to control the climate inside the greenhouse carefully enough and have sufficient supplemental LED lighting to get you through the winter months, you can maintain year-round growing conditions in a greenhouse. 

What Temperature Should a Greenhouse Be for Cannabis?

While the precise temperature you want will vary depending on different stages of the growing cycle and different times of day, the ideal range is between 65 and 85 degrees. Generally speaking, you’ll want to keep your plants warmer during the vegetative stage of the life cycle, then slightly cooler during the flowering stage.

Greenhouse Grown Cannabis from SunMed Growers

At SunMed Growers, we’re proud to cultivate high-quality greenhouse cannabis. We believe in the power of combining nature with technology to produce consistent, exceptional cannabis for both medicinal and recreational use. Why not find a dispensary near you and experience SunMed cannabis for yourself?