study on outdoor vs indoor marijuana cultivation

Indoor vs. Outdoor Weed: A Visual Guide

This guide was created to help sift through the endless varieties of cannabis we now have available to us at dispensaries. Now, this doesn’t apply to all strains, because every strain has different characteristics and grows different with every farmer’s care. However, these tools can be used to help analyze the often subtle differences between cannabis cultivated outdoor or indoor. At the end of the day, cannabis is a diverse and incommensurable plant — not all distinguishing factors will apply to every situation because every strain is unique.

It’s important to note that buds can be grown properly or improperly regardless of whether they were grown inside or outside, so improperly grown indoor can visually look like outdoor, while properly grown outdoor can easily look like indoor. But there are some standard tell-tale signs that cannabis has been grown inside or outside, so sit back and enjoy our visual guide to indoor vs. outdoor marijuana.

First let’s get a base calibration to see where you are starting.

Can you differentiate which one was cultivated indoors and which was cultivated outdoors?

If you guessed A was outdoor and B was indoor you are correct! Now let’s find out how you can easily differentiate how cannabis was grown through some strategic visual clues.


The sizes of the buds are, in many ways, the first visual cues to tell whether buds were grown indoor or outdoor. But it is a general rule of thumb that everything is bigger with outdoor-cultivated buds. The buds themselves are bigger and chunkier, but one of the most foolproof ways to differentiate the two is by looking at the stem. Outdoor grown buds will have a significantly thicker stem than indoor cultivated nugs. Indoor buds will typically be smaller and more dense than outdoor’s big, clunky nugs.

Trichome Density

Trichome density is a key visual cue when attempting to differentiate between indoor cultivation and outdoor cultivation. Because indoor buds are smaller, closer to their light source, and in a perfectly controlled environment, they typically rank very high on the trichome density scale. So when examining an impeccably grown indoor nug all that can be seen is glimmering crystals with very little plant material visible. Outdoor nugs on the other hand are generally larger, so those trichomes would have to work much harder to cover the entire surface of an outdoor bud. Additionally, outdoor plants are subjected to the elements which can damage trichome development. So the trichome density is typically more sparse on outdoor-cultivated nugs than ones grown indoors.

Example of high trichome density on indoor cultivated buds.


One of the most significant visual characteristics that can be used to differentiate sun-grown cannabis versus indoor-grown cannabis is the color. Outdoor cannabis tends to have a darker hue in general. If the cultivar produces green flowers, outdoor nugs will appear a darker green, possibly leaning towards brown if not cured correctly, while indoor buds will be a brighter, more vivid green. If the cultivar produces purple flowers, outdoor buds will turn a deep, striking purple while indoor nugs will stay lighter shades of purple (unless the strain’s genetics produce dark purple buds in any condition).

Another visual cue is the color on the bottom of the flowers. Buds cultivated outdoors almost always have a light brown color surrounding the stalk at the base of the bud (don’t worry it’s not mold). Usually, the tiny bracts at the bottom of the stalk will be a light brown as well. Indoor buds, on the other hand, are bright green (or purple) throughout.

Example of a darker hue on outdoor grown Lemon Kush.


There is a widespread myth that outdoor cultivated cannabis is less potent than indoor-cultivated cannabis. Simply put, that’s just not true. The dedicated farmers at Sunna Ra Acres have busted this myth once and for all. For the last few years, they have been conducting side-by-side tests of two clones taken from the same mother plant, one grown outdoors and one grown indoors. They’ve executed this experiment with a variety of strains and each time, the plant that is cultivated outside under the sun results in a higher overall cannabinoid profile. That means higher in THC, higher in CBD, higher in THCv, etc. Their experiment has shown that the sun unleashes the plant’s true potential and heightens its medicinal power.


In this case, terpenes are very similar to cannabinoids in that their profiles are intensified by the sun. In Sunna Ra Acre’s many years of experimentation they have found that if two identical plants are grown “side-by-side” — one grown outside, one grown inside — the plant that is grown outside will have a higher percentage of terpenes. And in some cases, the plants even reveal terpenes no one knew were there. When these two plants are smoked, the difference is very distinguishable with the outdoor being much more flavorful and aromatic. With that said, terpenes are volatile, meaning they will evaporate without proper drying and curing processes. Many indoor growers take greater care in their final stages of drying and curing because they yield far less and their product moves from one indoor room to another, providing more control through the process. New outdoor growers versus seasoned outdoor growers may overlook the step of proper drying and lose their high-terpene profile as a result.

Trim Job

While this category is very subjective and does not always apply, historically, outdoor growers spend less time trimming their final product than indoor growers. This typically has to do with the amount of bud harvested, outdoor growers are pulling down 5, 10, or 20 lbs per plant while indoor growers are pulling down 0.5, 1, or 2 lbs per plant. Trimming mass amounts of weed per plant would not only take weeks, but a big full-time crew would be needed. So the end result is usually a looser, leafier trim job — especially because outdoor plants are leafier in general. So while not always applicable, you can typically spot the difference between outdoor and indoor pretty immediately by scoping out the trim job.

Running through all these characteristics, with some give and take, while analyzing the hundreds of buds available for purchase at your local dispensary will help you to differentiate the outdoor grown from the indoor grown. If you are lucky enough to have access to the same flower cultivated both indoors and outdoors, it is amazing to smoke them side-by-side and compare the flavor profiles versus bag appeal. Indoor typically has better bag appeal while outdoor has the better flavor profile — it’s all about what you’re looking for in your daily smoke.

Before we go, there is a huge elephant in the room that we have not discussed today and that is greenhouse cultivated cannabis. Greenhouses are can be categorized as indoor cultivation using the power of the sun. It is the perfect marriage of indoor and outdoor because you have the environmental control of indoor but the incredible power of the sun. The result is typically buds that have the bag appeal of indoor with the elevated terpene and cannabinoid profiles of outdoor.


Can You Smoke Brown Weed?

Yes, you can, but it’s not going to be as potent or flavorful. The three things that degrade cannabis are heat, light, and time. When brown in color, weed has lost some of its potency and therapeutic value as the cannabinoids, such as THC, have been degraded. In addition, it’s lost a lot of its smell and flavor as the terpenes have potentially oxidized or evaporated. Smoking brown weed will not severely injure you or make you sick, but it is not suggested for use.

Ultraviolet (UV) rays from the sun do break down your cannabis over time. An oft-referred to study from 1976 at the University of London said light is the No. 1 reason for cannabinoid breakdown. If it’s burnt or overexposed to the sun during the growing process, weed will appear brown in hue. The color is due to sun damage on the colas of the plant, and it’s been shown cannabidiolic acid (CBDA) can transform into cannabidiol (CBD) with enough exposure, and THCV will degrade into CBV . In that case, some THC could still be intact, but the cannabinoids were at least partially transformed, or decarboxylated out of the plant by the sun.

How Much of a Difference in Quality is Outdoor vs. Indoor Weed?

There is high-quality weed both grown indoors and outdoors, but there are certain factors that determine the quality of the end product.

Between indoor and outdoor cultivation, the distinguishing factor in quality is the control of its environment. Factors such as temperature, light, water, humidity, carbon dioxide (CO2) exposure and care are going to be easier to control during indoor cultivation. While some strains may appear to grow a bit wilder outdoors, they are capable of developing the same amount of cannabinoids and terpenes as indoor-grown cannabis. Because of the unpredictability of nature, outdoor growing often requires a tepid climate.

The biggest case for growing weed outdoors is energy efficiency. Using all sunlight, or even just partial use of sunlight, to grow cannabis can save home growers and large-scale producers a lot of money in energy consumption. To take advantage of daylight and to take into account its variation during the year, many facilities have adopted a supplemental light grow in states where regulations permit it. Supplement light means the growers are using the sun when they can and then use lights when sunlight is unavailable, if the weed needs it.

The quality is mainly dependent on the seeds, the grower’s experience, and the care, not whether it was grown indoors or outdoors. Outdoor cultivation has a long history in Northern California ; the Emerald Triangle of Humboldt, Mendocino, and Trinity counties got its name because of its ideal climate for outdoor cultivation. In a handful of legal cannabis states, regulations may require grows to be indoors and hidden from public view.

Indoor vs. Outdoor Weed: A Visual Guide This guide was created to help sift through the endless varieties of cannabis we now have available to us at dispensaries. Now, this doesn’t apply to all

Sungrown vs. Indoor Cannabis Cultivation

Blessed with ample sunshine and a conducive climate, Hawaii also has some of the richest, volcanic soil suitable for growing cannabis outdoors. But recent medical marijuana regulations crafted by Hawaiian officials mandate that all cannabis grown for dispensaries must be cultivated indoors.

Several other U.S. states where medical marijuana is legal have also banned outdoor cannabis cultivation. Even in sunny California, local officials have the option of requiring that cannabis be grown indoors. Much of the cannabis sold in California’s medical marijuana dispensaries is grown under artificial lights. Indoor cultivars are quite popular among cannabis consumers who favor “bag appeal” when shopping for herb. “Bag appeal” generally refers to trimmed and cured cannabis flowertops with the right combination of appearance, smell, and strain name that resonates with medical patients, blue collar stoners, and weed snobs.

Most agricultural crops throughout the world are grown solely outdoors: grapes to make wine, for example. It wasn’t so long ago that cannabis was exclusively grown outside as well. That changed because of marijuana prohibition and the need to avoid detection by surveillance helicopters and police. Indoor cannabis cultivation took root in a big way in the United States during the 1980s when the Reagan administration escalated and militarized the war on drugs. Frequent law enforcement raids that targeted outdoor gardens inadvertently helped to jump-start a cottage industry of innovative products and accoutrements for growing marijuana indoors—all manner of nutrients, soil amendments, special lights, and various gizmos to control temperature and moisture. Cannabis, a versatile botanical that can thrive under a diurnal or 24-hour light cycle, adapted well to the new indoor environment.

But which cultivation method produces better cannabis—sungrown or indoors? Is there an appreciable difference in quality between the two? Some cannabis consumers swear by indoors; others prefer outdoors. Here is a breakdown of the pros and cons of each:

Sungrown Pros

  • Low carbon footprint and lower costs. Sungrown cannabis requires far fewer resources and is less expensive to produce than plants grown indoors. Sungrown uses the natural environment to fuel its growth, and it does not require artificial, high-intensity lighting. Compared to indoor grown cannabis, sungrown plants typically require less soil amendments, fertilizers, pesticides and fungicides. Indoor power usage and water usage is very resource consumptive. Evan Mills reports in Energy Policy that an average kilo of cannabis grown indoors is associated with 4600 kilograms of carbon dioxide emissions into the atmosphere. “From the perspective of individual consumers, a single Cannabis cigarette represents 1.5 kg (3 pounds) of CO2 emissions… The energy to produce one marijuana cigarette would also produce 18 pints of beer,” according to Mills, who adds: “There is little, if any, indication that public policymakers have incorporated energy and environmental considerations into their deliberations on cannabis production and use.” Although indoor growers can utilize sustainable energy solutions such as solar power, sungrown cannabis, with its much lower carbon footprint, will always prevail in the sustainability competition.
  • Complements the plant’s natural life cycle. For millions of years, plants that undergo photosynthesis have evolved and flourished under the rays of the sun. Scientists report that cannabinoid and terpene production is greatest in ambient light. Natural light is much more complex than what even the best grow lights can mimic. Unlike indoor plants, outdoor cannabis is exposed to a full spectrum of light from the sun, moon, and stars. Outdoor cultivation also enables natural airflow and ventilation; no electric fans are necessary. It’s impossible to duplicate nature’s supreme design when growing cannabis indoors.
  • Ecology and resiliency. Acclimated to local conditions, unique landrace varietals native to specific bioregions (Acapulco Gold, Panama Red, etc.) have adapted to deal with local pests and other threats. Because outdoor crops are part of the ecosystem, the plant interacts with the elements and this helps to build flexibility and resistance to temperature fluctuations and potential attacks. Healthy plants are less susceptible to the invasion of mold, mildew, and predators in general. Organic farming methods can preserve and enhance the complex biota of the earth’s soil in a way that retains carbon and helps to offset global warming. When growing outdoors, a farmer has more liberties to implement sustainable methods of cultivation, such as the permacultural techniques of companion planting. These methods utilize various natural techniques to sustain a thriving ecosystem: intercropping (with plants that compliment cannabis), planting ground cover (which keeps in water and nutrients), and introducing beneficial bugs. Companion planting avoids growing in a monoculture and brings in a variety of plant species to implement complementary natural pest management which contributes to a diverse, healthy ecosystem. This is possible to some degree with indoor growing, but the opportunities for permaculture techniques are limited indoors.
  • Therapeutic horticulture. Cultivators who work with sungrown plants get a good dose of nature therapy just by being outdoors. That’s especially important in a society where people are generally disconnected from their natural environment; getting outside can help to balance this deficit. An essential source of Vitamin D and much more, sunlight is intrinsically therapeutic. According to an October 2016 study in the Journal of Internal Medicine, sunlight deficiency can be as harmful to human health as cigarette smoking. Outdoor cannabis farmers also benefit from bathing in the symphony of smells and organic aromas indigenous to the local terroir. Plants communicate with each other and their cohabitants, especially insects, by releasing odiferous compounds known as terpenes in response to environmental stressors. Some plant smells attract beneficial bugs; others repel predators. It’s our good fortune that many of the same compounds plants generate under stress have medicinal properties that help human beings cope with stress.

Indoor Pros

  • Year-round cultivation. Indoor cultivation isn’t seasonal. With the right set-up, indoor growers could theoretically produce cannabis any time anywhere in the world. They are not limited by adverse environment conditions that may impact outdoor farmers who can only grow in favorable climates. Indoor cannabis can grow all year round in otherwise inhospitable areas, where dampness and rain would increase the likelihood of mold infestation and disease if the plants were outside. Although the yield of indoor grown plants is generally less than that of a comparable number of outdoor plants, multiple indoor grows throughout the year will produce more cannabis than an outdoor summer garden.
  • Control over growing conditions. Indoor cannabis plants are more sensitive than outdoor plants and, therefore, a cultivator must carefully monitor and adjust various factors within a closed, interior grow-room. A skilled indoor grower is able to control all aspects of light, air flow, soil, and nutrients that affect the plants. If done well, this creates an ideal situation for breeding purposes, research and development, and the preservation of unique genetics. For example, if a cannabis cultivar has an attractive purple color that appeals to consumers, indoor production can focus on that characteristic and target it in upcoming generations of the plant’s life cycle.
  • Product standardization. As the cannabis industry matures, consistency and predictability will be required to standardize a medical product and to gain approval in the pharmaceutical sphere. Standardization is necessary for a reliable, reproducible product that can be researched during clinical trials. In order to achieve such standards and protect plants from unwanted influences, there must be regularity and consistency in every aspect of the growing procedure—water, light, humidity, pest management, etc. This can be very challenging for even the most meticulous outdoor cultivator, as it is difficult to control humidity, fungal infestation and other environmental factors that can adversely affect a sungrown cannabis crop.
  • “Boutique” production. Cannabis consumers want a nice looking product with a stellar aroma. Dispensaries place a premium on “bag appeal” when displaying cured cannabis flowertops. A skilled indoor grower can carefully manipulate various environmental factors to accentuate desired traits, resulting in cannabis that looks great and smells divine. This in turn translates into a more valuable product when cannabis goes to market. A common misperception is that the potency of cannabis grown indoors is higher than sungrown cannabis. (“Federal sources as well as independent testing labs actually find similar potencies when best practices are used,” according to Mills.) Yet, indoor cannabis tends to fetch a higher retail price than sungrown, which costs less to produce. Outdoor growers are able to cultivate their crops with minimal overhead, less equipment, and less electricity, but the lower price-tag doesn’t necessarily mean lower quality medicine. Again, it’s largely a matter of perception and bag appeal.

Best of Both Worlds

There is a third option for cultivating cannabis, one that combines the best of both worlds, indoors and outdoors. Cannabis thrives in a well-designed greenhouse. A greenhouse grow-op can harness sunlight all year round, while allowing a skilled horticulturist to precisely control environmental factors that protect plants from contamination and infestation. The sun’s rays can also be manipulated by a technique known as light deprivation (“light dep”), which can change the daily grow cycle in a greenhouse so that farmers can harvest three or four crops per year—much like indoors but without excessive energy consumption. In many respects, a greenhouse offers the perfect combination of a controlled, consistent growing process that also utilizes natural sunlight.

Whether grown outdoors, indoors or in a greenhouse, cannabis should be tested for pathogens, pesticide residues, and other contaminants before it goes to market. Cannabinoid and terpene content should also be included on product labels. A true “top shelf” cannabis product would meet all these criteria irrespective of price and bag appeal. There is no reason why cannabis consumers should not have access to a wide array of options in terms of strain type, THC and CBD ratios, modes of administration, and price-point, as well as diverse methods of cultivation. Demand high quality standards for your medicine, no matter how it was grown. And let’s not forget where cannabis came from: the earth.

“One touch of nature makes the world kin.”—William Shakespeare

Sarah Russo is the Creative Director for Project CBD , a self-taught lover of herbs, and an avid globetrotter. She is currently based in Granada, Spain.

Copyright, Project CBD . May not be reprinted without permission.

A special thanks to DJ Short, Brooke Carpenter, Caitlin Podiak, Chrystal Ortiz, Cameron Murdock, Ethan Russo, Nakona MacDonald, Emerald Pharms, Fiddler’s Greens, and others who contributed to the writing of this article.

photo credits: TC Johnny Apple, RaysAce & Gobiginternational Justice Genetics

Which growing method produces better cannabis – sungrown, indoors, or greenhouse? Here is a breakdown of the pros and cons.