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Growing Healthy Marijuana Through The Winter. Snow falling on a cannabis plant.

Growing Healthy Cannabis Through The Winter

The fall outdoor cannabis harvest has come and gone, and cultivators are now enjoying profits and the fruits of their labor. There is a large market for organic outdoor cannabis, with some consumers considering it a superior product. Outdoor cannabis is becoming more widespread as businesses and customers alike recognize there is a demand for it, and it allows an entirely new opportunity as far as marketing goes.

Because of its size and warm climate, California will no doubt be the main producer of superior cannabis that’s grown outdoors. The state already has a long history of outdoor marijuana production since it’s home to the Emerald Triangle (Trinity, Mendocino, and Humboldt Counties), a region with generations of outdoor cannabis growers. Even the name “Humboldt” is nearly synonymous with potent cannabis. But even Humboldt’s hospitable climate doesn’t allow outdoor cannabis production during the winter months.

Crop-growing regions of California, like the San Juaquin Valley and Salinas Valley, supply the country with most of its walnuts, oranges, peaches, garlic, strawberries, and numerous other crops, which earns them the monikers of “America’s food basket” and “America’s salad bowl” respectively. These and other areas of the state have outstanding climates for agriculture, so there’s no denying its superior conditions for outdoor cannabis growing.

Outdoor cannabis crops have the potential for huge yields. Plants grown outdoors in properly prepared soil can go directly into the ground, which allows for enormous root development and upward growth. Marijuana plants that are 12 feet tall or taller are possible in northern California’s prime growing regions and other regions with warm enough climates for long growing seasons. Since sunlight is free for outdoor cannabis cultivators, their crops leave less of a carbon footprint than their indoor counterparts equipped with grow lights.

The onset of winter, however, doesn’t mean that cannabis production has to cease for outdoor growers in California and other areas of the country. Both commercial operations and home growers can transfer their endeavors indoors or artificially simulate longer days in greenhouses. Greenhouses properly equipped with supplemental grow lights and heat can extend cannabis cultivation throughout the fall and into the harsh winter months. These greenhouses can capitalize on Mother Nature’s solar energy and also utilize grow lights to extend short winter days to replicate the longer days of spring and summer.

The Indoor Grow

Most winter cannabis growing, however, will be done indoors. The majority of home growers already rely on an indoor environment for winter growing. Although done on a larger scale, commercial operations can continue to increase their profit margins by growing winter crops indoors. While indoor growing is more expensive, there are some significant advantages.

Indoor winter growers operate in a completely controlled environment with regard to temperature and humidity and length of day by relying on artificial means. The protective indoor environment shields plants from harsh outdoor weather conditions like wind, rain, and hail—which can have a devastating effect on prime cannabis. Indoor growers can also capitalize on the use of CO2 in their grows, which would be impractical and useless outdoors where CO2 would dissipate quickly due to breezes in the expansive outdoor environment. Plants supplemented with CO2 grow significantly larger indoors than plants grown without it.

Unfortunately, regardless of unique benefits that indoors growers enjoy, the cost of growing indoors is significantly more expensive than growing outdoors.

Indoor Growing Expenses

Because indoor grow spaces are controlled environments, quite a bit of gadgetry can go into them. While some indoor operations, especially home grows, can sometimes get away with minimal equipment, just about all commercial cannabis growers will want as much control over indoor environmental factors as possible.

To learn more about the additional costs associated with indoor growing, let’s consider some of the standard equipment and related expenses that are an inevitable part of indoor growing. While some expenses are part of getting operations up and running, other costs are ongoing. Not all of these expenses are unique to indoor winter growing, but many of them are—and they can add up fast.


Growing cannabis indoors requires a great deal of electricity. Outdoor grows have a distinct advantage, because natural sunlight is free. The expense of running multiple grow lights for 18 hours per day can result in hefty electric bills. Costs subside somewhat when light cycles are reduced to 12 hours to induce flowering, but the expense can still be significant, even with small home-grow rooms.

Grow Light

Growing high-quality cannabis indoors requires specialized lighting, and these lighting units can be expensive. Whether the lights are high-pressure sodium (HPS), metal halide (MH), or light-emitting diode (LED), which can all grow top-drawer cannabis, the cost of these units is much more than conventional lighting. The good news is that these lights are usually quite durable and can last for years before replacement units are necessary.

Light Bulbs

HPS, MH, and LED light bulbs are expensive and require regular replacement for top performance, well before the lights burn out on their own. The quality of light rays produced by them degrades fairly fast, so replacement should occur after a few harvests, if not sooner. Using fresh bulbs will result in more robust plants and higher yield.

High-Drainage Pots

Not all pots that are intended for plants are created equally. Cannabis plants thrive in pots with high-drainage capacities. There should be numerous holes to accommodate the release of excess water. Pots that do not drain well can result in the collection of unnecessary water that can stagnate, which is detrimental to the plants’ root systems. Air Pots® and smart pots work very well for cannabis and have superior drainage. While these pots are reusable, the initial cost is much more than conventional nursery pots.

Organic Soil and Soil Additives

Cannabis consumers prefer organically grown product. Whether you create your own soil mixes with compost and other ingredients or purchase organic bagged soils, the cost is significantly higher than regular potting soil. Likewise, organic soil additives (fertilizers) will cost more than synthetic additives. Some strains of cannabis can absorb high quantities of these additives, which sometimes means purchasing them by the gallon is the best alternative. Small bottles won’t last long.

Fans and Ducts

All cannabis grows should have good air flow and ventilation, which will reduce excessive humidity and ensure the regular replacement of fresh air in the room. Standard oscillating fans on vertical stands will serve this need well. Fortunately, they are inexpensive, as are standard ducts for room ventilation. Ducts that include forced-air capabilities can be significantly more expensive, although the plants will benefit from regular fresh air.

Meters and Gauges

The controlled indoor environment, particularly for commercial grows, will benefit from monitoring temperature, humidity, and water quality. Although the cost of these meters and gauges can run high, inexpensive examples will usually suffice. Thermometers, humidity gauges, and pH meters should be standard equipment for indoor growing to ensure optimal conditions for cannabis cultivation.

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Miscellaneous Equipment

There are number of other components that may or may not be necessary for indoor growing. These include thick plastic sheets to contain water drainage and protect floors, and sheets of reflective mylar to cover walls (bright-white paint on the walls also works fairly well—but mylar is better). Water filters and pH boosters or reducers may also prove necessary depending on water quality. Pot saucers and trays may be advantageous as well if the grow room is not equipped with floor drains, and this is not a common feature for most home grows. Excessive water in the room can lead to overly high humidity.


When the days grow shorter and the fall chill sets in, growing outdoors is no longer an option. Regardless of this reality, there’s no reason to pack it in and cease cannabis crop production. The indoor winter grow will provide an abundant supply of excellent flower. The approach is somewhat different, and the costs are higher, but a good crop will pay for these expenses many times over. Plan carefully beforehand, and your growing operation will continue seamlessly and quality will remain high.

Luis Cordova
Luis Cordova

Luis Cordova is a distinguished author, and renowned expert in cannabis cultivation, who possesses a Master's degree in Plant Biotechnology and Pharmaceutical Science. As a valued contributor to highly esteemed publications such as Cannabis Training University and Maximum Yield Magazine, Luis has emerged as a trusted source of guidance and knowledge in the cannabis industry. Having written thousands of informative articles, Luis is widely recognized for his comprehensive expertise on cultivating cannabis, both indoors and outdoors.

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