Cannabis may be bright and green, but *sustainable* is usually not the first adjective that growers would use to describe their grow tents. As a heavy-feeding, high-maintenance, high-value crop, cannabis needs a lot of specialized care to go from seed to harvest. Summer growers can offset their energy costs by relying on sunshine and rainwater provided by the bounty of nature. In the dead of winter, however, grows are confined to greenhouses and grow tents.
This increase in energy and water consumption not only puts strain on your utility bill but also contributes to your carbon footprint. Cannabis growers are often at the forefront of greenhouse innovations, many of which are dedicated to improving efficiency. In 2025, we’re moving into a new age of cannabis growing by cultivating cleaner and greener plants that reduce our impact on the environment. Here are some tips for achieving your green growing goals!
Track Your Usage
The best way to know how to reduce your environmental impact is to track your current output and determine where you can make adjustments. It’s easy to figure out how much energy you use in your grow tent, and by reducing your energy consumption you can actually make it cheaper to manage your grow tent!
1. Identify Kilowatt Hours
Every grow room is kitted out with a different collection of electronics: from grow lights and HVAC to fans and watering systems. Each of these electronics has a wattage label that will tell you how many watts of energy they consume in an hour. Take note of the electronics you’re using and their wattage labels. Divide this number by 1000 for each of the devices you’re powering and the result is the number of kilowatts they consume in an hour.
2. Determine How Much Power You’re Using
Cannabis has fluid needs as the plant continues to grow and develop, the easiest example of this is changes in lighting needs. We’ll walk you through how to calculate your energy output with lighting, but you can tailor this method to all your devices, and your growing technique.
First, calculate your daily use of each device. How many hours do you use this device per day? Then, multiply this number by the days of the week you use this device. Finally, multiply your final number by the number of weeks you use the device. This will give you the total energy cost for one grow cycle. Much of your machinery will be consistent throughout your grow cycle, but lighting will change at several key points in the grow cycle.
Seedling Phase
There is a lot of grower debate on how much light to give developing seedlings. Germinating plants prefer darkness, you can leave the lights off until the seed is cracked. But once you see green, the lights should come on!
Some growers prefer to maximize light output by running a 24:0 cycle where the plants don’t receive darkness until they’re potted up. Others prefer to run with 18:6, to introduce the day/night cycle to their plants. Plants perform essential functions during the night cycle, as this is when plants ‘seek’ in the soil with their roots. Choose whichever method works best for you! The energy benefit of the seedling phase is that you can use a lower-power light for seedlings and grow more seedlings under a single light. Some strains may only need one week to develop before being potted up, while others may need 3-4. This growth stage is specific to your plant’s needs, so your energy cost can vary depending on how quickly or slowly they grow. The benefit of the seedling stage is that you can fit all of your tiny seedlings under one lamp, starting you out with lower energy usage.
To calculate your KW usage:
((Device wattage/1000) x Number of Devices Used) x (hours of light/day x 7 days/week x 3 weeks)= Total KW Used
Vegetative Phase
The vegetative phase has the most extensive light demands, with 18 hours of light and six hours of darkness. With plants growing larger in this stage, you will have to space them out and increase the number of lights used compared to the seedling phase.
To calculate your KW usage:
((Device wattage/1000) x Number of Devices Used) x (18 hours/day x 7 days/week x 6 weeks)= Total KW Used
Flowering Phase
Flowering is triggered by the light pattern changing from 18 hours of light during the daytime to 12 hours of light, simulating shortening daytimes and the end of the growing season. Compared to vegging your plants, flowering is a period during your plant lifecycle where you naturally decrease your environmental impact. Your flowering duration will depend heavily on the strain you’re cultivating, genetics, and other environmental factors, though 9-10 weeks is fairly standard.
To calculate your KW usage:
((Device wattage/1000) x Number of Devices Used) x (12 hours/day x 7 days/week x 10 weeks)= Total KW Used
3. Finding Alternatives
The easiest way to lower electricity consumption is to find lower-wattage devices. Swapping standard lights out with LEDs is becoming an industry standard. Check the wattage rating on old equipment and look for updated alternatives that can lower energy usage. In some growing spaces, adjusting your layout and improving air circulation can lower reliance on fans and air conditioners, allowing you to limit usage hours and cut down on energy costs.
Powered by Nature
Indoor cannabis growing is infamous for eating up energy, with a 2012 study showcasing that indoor cannabis growth accounts for approximately 1% of national electricity use in the USA. Rather than relying entirely on your standard power supply, supplement it with eco-friendly energy! Solar panels are widely available and easy to set up, making them an excellent choice. There are also small wind turbines that can add to your energy supply, though these are still fairly large and not as subtle as solar panels.
There are many options available for a greener 2025. Alternative energy doesn’t have to replace your existing power supply to make a difference!
Water Wisdom
Outdoor cannabis plants can need up to 22 liters of water per day, much of which is absorbed into the soil. Indoor growers know that cannabis in grow pots does not need nearly this much in the way of water, but it is still an essential nutrient that is easy to waste.
The first way you can save water for indoor grows is to literally save water! Collect rainwater, snowmelt, and condensation from air conditioners, and use these natural sources of hydration to feed your plants. If you’re growing in soil and experience a lot of runoff, you can save this runoff and recycle it back into your growing program. If you see more than 1-10% runoff, try reducing the amount of water you give your plants in a single application. A lack of runoff isn’t a bad thing, just watch your plants for signs of dehydration.
Soil that’s rich in organic matter will naturally retain water. Growing in a compost-based premium mix like IndiCanja, or amending your soil with Activated Compost can reduce your watering frequency.
Maximize Your Space
A lot of the base costs of your growing operation are unavoidable. Especially for indoor growers, it’s difficult to whittle down your energy use when you rely so heavily on electronics. Maximizing the number of plants in your grow space can help you to even out energy usage, meaning you get more produce out of every grow cycle and lower your cost-per-gram on overhead. Wholesale growers have long since relied on space maximization to get the most out of each greenhouse cycle, with the Sea of Green method being invented to generate as many plants in a small grow area as possible. For growers who don’t want to run SOG, you can also experiment with vertically stacking your plants, making use of under-utilized space.
Greener growing is easy to achieve and can reduce your environmental impact alongside lowering your bills. Set a goal for yourself this year to lower your electricity usage, or experiment with natural replacements for things you regularly use in the grow tent. For more information on setting green grow goals for 2025, contact our team of experts!