The humble cannabis plant’s needs become very demanding when she has to fulfill our medical and recreational expectations. She requires a proper climate, a lot of light and water, and some extra nutrients. As a consequence, growing cannabis both on a commercial and domestic scale has significant environmental impacts because of power consumption, water usage, and polluting wastewater.

In North America, cannabis cultivation utilises 1% of the total electrical consumption in the continent just to power high-intensity lamps and cooling systems. The result, believe it or not, is more than 4,600 kilograms of CO₂ released into the atmosphere for every kilogram of cannabis flowers grown indoors. In some states or regions, indoor cannabis production is responsible for more than 3% of the overall electricity bill, not to mention water consumption and waste materials rich in heavy metals and other contaminants running almost inevitably into aquifers after being drained from the plants.

One of the issues faced today by the global cannabis community concerns the attempt to make this industry greener for real, not just on merchandise stuff. Sustainable growing practices are now needed, and while we hope that legalization will also bring about more sustainable mindsets in the greater cannabis industry, we too can contribute as small cannabis growers to the reduction of ongoing environmental damage.


Even forgetting for a while about the environmental impact of our small operation, we know that maintaining a homegrow can be quite expensive. Recurring energy-related costs are a significant financial burden when running an indoor operation. The combined energy costs for grow light systems, fans and air extractors, humidifiers and air conditioners, heaters, and other energy-sucking devices can quickly get pretty high.

Outdoor cannabis grows are certainly more sustainable. Sunlight, wind, and rain are free, and infinitely more environmentally friendly. However, outdoor cannabis gardens need more pesticides, fertilisers, and water than indoor operations. Moreover, improper cultivation practices can quickly impoverish and erode the soil.

Whether you grow just a few plants for personal use or you own a commercial operation, the cultivation techniques and the tools you decide to work with all have an impact on the environment and on recurring expenses. Fortunately, the energy requirements can be mitigated through smart planning and device purchase, while the polluting waste material can be brought to almost zero, even improving the quality of the final product. Here are four main elements to consider for sustainable cannabis growth: energy consumption for lights, energy consumption for climate control, water consumption, and waste management.

Sustainable Outdoor Growing


Bulbs get hot and require constant ventilation in order to keep the grow room temperature within the necessary range. The first environmentally friendly tip is completely free: when possible, just invert the day/night period and run your lights at night. This method takes advantage of the natural cool night air, reducing the need for heat extraction and allowing the fans to run at low power. Humidifying devices can also run lower. Plus, night electric fees are often cheaper than during the daytime.

Another good free practice is to think about the ideal size of the grow. You don’t want to waste any illuminated space, but you do want to ensure your light output is received equally by all the plants. Growing techniques such as screen of green (ScrOG) can be used to achieve equal light distribution to all parts of a plant. When possible, combining grow lights with some genuine direct sunlight is another great and free way to please plants and save something on the electricity bill.

LED lights use less energy than any other grow light to achieve comparable results, resulting in the most sustainable grow light system for a small indoor garden. Their higher outright cost is compensated by a longer lifetime, and the little heat generated by LED lamps doesn’t require a powerful hot air extractor.

If the grow room works with magnetic ballasts powering traditional high-intensity discharge lamps (MH lamps for veg and HPS lamps for bloom), upgrading to electronic dimmable ballasts is an expense that will pay off over time with lower heat and electrical consumption. This kind of ballast also allows you to regulate the power that is sent to the lamp, and its stable power flow increases the lifetime of HID bulbs.


The different seasons of the year often have an impact on indoor operations too. This should be taken into account when choosing and germinating a strain, or designing climate control systems. Before buying a new powerful fan or air conditioner, the responsible grower should consider if natural solutions for better climate control are possible. Careful planning and testing of the airflow pathways in the grow room can optimise temperature and humidity without the need for further devices. Pumping air into the grow directly from outside or from another room can also make a big difference in terms of climate.

The extracting tube vents should always be adjustable in order to reduce the airflow when temperatures aren’t too high. This helps maintain a proper climate and save energy, while an excess of ventilation is useless and also causes a drop in humidity that must be compensated with other power-sucking devices. Once again, when possible, move the plants outside to let them and your wallet benefit from natural light and cooling systems.

Air Flow Cannabis Outdoor


Cannabis is a thirsty plant, but the home-grower can’t help so much with this, apart from avoiding an excessive waste of water. The main problem comes when the cannabis grow is not organic (which happens in most commercial operations). In this case, the drain water will contain fertilisers and maybe pesticides, and it also has an unbalanced pH.

Desalination and reverse osmosis systems can reclaim most of the water used during growth, but these technologies require an additional investment and maintenance effort. Collecting rainwater is a great and simple way to save water and feed the plants with chlorine and calcium-free water. Unfortunately, this good practice requires additional space outdoors, and usually it doesn’t rain enough when water is needed most.


Organic cannabis growing practices can make the plant greener and the garden more sustainable. They are better for the plants and ideal for consumers, but organic crops are more expensive. And organic cannabis is very hard to find on the market. Nevertheless, organic gardening can save money in the long-run, and is potentially less expensive than an intensive indoor, or even outdoor, cannabis cultivation operation.

Organic crops start from the soil. A well-prepared organic growing medium requires few amendments over time, and the nutrients it contains are readily available for the plants because of the action of beneficial microorganisms. Of course, this method requires making compost, and eventually also a supplemental mix of natural fertilisers. If the grower is lazy, or making compost is not convenient, it is always possible to buy bags of good soil and bottles of organic nutrients directly at the local grow shop. One thing is for sure: no harmful chemicals and inorganic fertilisers are allowed.

Same concept applies to pesticides. The rule is replacing industrial pest control chemicals with biological organisms or products that are able to eat or keep parasites away. Organic pest control techniques are based on plant diversity in the same garden, on the introduction of beneficial insects and microorganisms, and on natural compounds sprayed on the leaves to annihilate parasites.

Organic Soil And Pesticides


Greenhouses quickly became popular in the blooming cannabis industry because they can leverage both the benefits of the sun and a controlled environment, protecting the crops from natural adversities. With an integrated technological environment made of sensors, smart climate-control devices, high-efficiency bulbs with fine-tuned light emission, and honed-in feeding programmes, today’s hi-tech greenhouses have reached a superior level of power optimisation, with the aim to improve the gram/watt ratio of the final product. A few growers have also started using some kind of artificial intelligence software to analyse data and determine the most efficient ways to produce the largest yields.

Even if the average home grow-op is not a big polluter and the goals are different from commercial operations, keeping an eye on how technology develops in the cannabis industry is a good habit that might translate into a more efficient and sustainable growing practice. Saving energy, growing organic, and reducing waste material should be a must for every home-grower who wants to be responsible, save money, and grow top-quality, pollutant-free cannabis flowers.

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