BackSimple and eco-friendly cannabis growing practices to reduce your environmental impact
26.03.2025
Sustainable cannabis cultivation is gaining more and more relevance in a world where environmental awareness has become a priority. As small growers, we have a unique opportunity to make a difference by implementing green practices that not only benefit the planet but can also improve the quality of our crops, reduce costs, and create a growing cycle that’s more in harmony with nature. Here we propose simple and original techniques, backed by the experience of real growers, which can transform your small grow into an example of sustainability.
Optimisation of water consumption
A highly effective practice is the implementation of rainwater harvesting systems, which can be as simple as placing barrels under drains. To maximise the efficiency of the collected water, improvised drip irrigation techniques can be used – you can use recycled bottles with small holes in the caps, partially buried next to the plant, and filled with water. This allows for a slow release of the water directly into the root zone. Another practice is the use of hydrogels, which are superabsorbent polymers that can be mixed with the substrate to retain water and release it gradually.
- Environmental impact: Less wasted water and zero electric power for automated irrigation. And you’re also reusing materials.
- Top tip: If you grow indoors, use a 500 ml bottle with a single tiny hole to control the flow even better. Adjust according to your plant’s needs.
Energy efficiency in indoor grows
For the home grower with limited resources, an effective practice is to use homemade reflectors made of cardboard and foil or reflective paint – these can increase light efficiency by up to 30% without additional energy consumption. You can also use soda cans cut into strips and glued around your LED lamp to direct the light towards the plants. Another common practice involves the synchronisation of the grow cycles with the electricity rates, scheduling the lighting periods during reduced rate hours (usually at night) to significantly reduce energy costs.
- Environmental impact: Less energy consumption and reuse of metal waste that often ends up in landfills.
- Top tip: Make sure the aluminium is well cleaned to avoid odours; and don’t use it with intense heat lamps (such as HPS), as it could melt.
Use of domestic microclimates
Natural microclimates within the home can reduce energy consumption in indoor grows. For example, placing your grow near a boiler or water heater allows residual heat to be used during the cold months, thereby reducing the need for additional heating. You can also use homemade storage heaters made with bottles containing black tinted water, which absorb heat during the day (or during the hours with lighting) and slowly release it at night, helping to maintain a more stable temperature with lower energy expenditure.
- Environmental impact: This lowers energy consumption by reducing reliance on air conditioning systems.
- Top tip: Place the black bottles on a reflective tray to maximise light and heat absorption; and check that they don’t obstruct the ventilation.
Composting and recycling of organic waste
Forget about buying expensive substrates. A technique that is gaining popularity is to create a "living substrate" with earthworms. Mix organic soil with kitchen scraps (vegetable peels, eggshells, coffee grounds,…), and add a few red worms (available in fishing or gardening shops). These decompose organic matter, aerate the soil, and produce castings (i.e., a nutrient-rich natural fertiliser). A "floor system" can be created by using overlapping pots with holes that allow the worms to move between the different levels, processing waste and continuously feeding the plants.
- Environmental impact: You reduce organic waste by recycling it at home whilst eliminating the carbon footprint associated with the production and transport of commercial substrates.
- For indoors: Use a pot with a perforated base and a tray underneath to prevent the worms from escaping.
Natural control of pests and diseases
Neem oil is a powerful repellent that discourages the most common cannabis pests. It can be mixed with natural potassium soap, which improves the adhesion of the oil to the leaves. Instead of insecticides, resort to natural allies and homemade traps. Release ladybirds (you can buy them online or in nurseries) so they feed on aphids and other bugs in your outdoor grow. Crustacean flour is another surprisingly effective solution, as it contains chitin, which stimulates the plant’s natural defence mechanisms. Or aloe vera gel, that not only fights fungi and bacteria, but also acts as a biostimulant.
- Environmental impact: You avoid toxic chemicals that pollute the soil and water, as well as supporting local biodiversity with the ladybirds.
- Note: Indoors, use a yellow adhesive tape smeared with honey to catch small flies.
Beneficial companion planting
Planting basil or mint around cannabis not only repels insects such as aphids and white flies, but it can also improve the aromatic profile of the flowers through terpene association. A less well-known technique is the use of trap plants such as sunflowers, which attract aphids away from cannabis, allowing the grower to concentrate the problem on expendable plants. Planting clover or vetch between seasons helps prevent erosion, improve soil structure, and add organic matter. Rotating cannabis with other plants, such as legumes that fix nitrogen, or crops that replenish nutrients, helps break pest and disease cycles, thereby maintaining soil fertility.
- Environmental impact: It reduces the use of chemical pesticides and improves soil health, preventing degradation due to monoculture.
- Top tip: If you use sunflowers as trap plants, position them about 30 cm away from cannabis so that aphids concentrate on them and are unable to jump to your plants.
Organic and sustainable fertilisation
Bat guano tea (which is rich in phosphorus, potassium, and nitrogen) is particularly effective during the flowering stage. To prepare it, just mix one tablespoon of guano for every two litres of water, and leave it to stand for five days. A surprising alternative is black sesame tea, which is rich in calcium and iron – it is made by mixing four tablespoons of sesame seeds with 1.5 litres of water, leaving it to stand for 24 hours. Another innovative option involves fermenting ripe fruit with molasses and water in an airtight container for two weeks, creating a concentrate rich in enzymes and nutrients.
- Environmental impact: This minimises dependence on synthetic fertilisers and makes great use of natural resources or organic waste.
- Top tip: For fruit tea, use apple or ripe banana leftovers (cannabis loves potassium), and shake the container every two days to avoid bad odours.
Small steps, big changes
Growing cannabis at home doesn’t have to be a burden on the planet; and, with these simple practices, you can reduce your environmental footprint without complicating your life. Best of all, these ideas, although uncommon, have been tested by growers like you in backyards and apartments all around the world. So next time you water your girls, just think: what can I do differently today? The planet (and your buds) will thank you for it!