The practice of “washing” cannabis, often called a bud wash, is a post-harvest technique used to improve the cleanliness and safety of the final product. This process involves briefly immersing freshly harvested cannabis flowers, still attached to their branches, in a specialized water-based solution. The primary purpose is to remove surface contaminants that accumulate during the plant’s growth cycle while preserving the integrity of the flower structure and its active compounds.
Rationale for Washing Cannabis
Washing harvested cannabis flowers addresses health and safety concerns by targeting various residues that can affect consumption quality. Plants grown outdoors are highly susceptible to environmental pollutants, including fine dust, airborne debris, pollen, and mild pest residues. Indoor-grown cannabis is not immune, often collecting dust particles and developing surface contaminants like powdery mildew spores.
These fungal spores are a concern because they can proliferate and pose a health risk if inhaled. Washing helps remove these surface layers, which can also include residual agricultural products. The beneficial compounds in cannabis, like cannabinoids and terpenes, are hydrophobic and oil-based, meaning they will not dissolve or wash away in the water-based solutions when the process is performed correctly.
Preparation and Necessary Materials
Successfully washing cannabis requires gathering specific materials and preparing a clean workspace beforehand. You will need a series of clean, food-grade containers, most often three five-gallon buckets, to create a washing assembly line. Filtered or reverse osmosis water should be used to avoid introducing impurities.
The first bucket contains the active cleaning agent, which is commonly a diluted solution of 3% hydrogen peroxide (one cup per five gallons of water). As an alternative, a mixture of one cup of baking soda and one cup of lemon juice per five gallons of water is often used. The remaining two buckets are filled with plain, clean water and serve as rinse stations.
The Step-by-Step Washing Procedure
The process begins by gently submerging a freshly harvested branch into the first bucket containing the cleaning solution. The goal is to fully immerse the buds without excessive force that could damage the delicate trichomes. The branch should be gently swirled or agitated in the solution for 30 to 60 seconds. After the initial wash, the branch is carefully lifted out and allowed to drip-drain excess liquid back into the first bucket.
The branch is then immediately transferred to the second bucket, which holds the first clean water rinse. Here, the branch is again gently swirled for about 30 seconds to remove the majority of the cleaning solution and any remaining contaminants. The final step involves moving the branch to the third bucket, which contains a final bath of fresh, clean water. This last rinse, also lasting around 30 seconds, ensures no residues remain on the flowers. Once complete, the branch is removed, given a gentle shake to shed surface water, and is then ready for drying.
Safe Drying and Post-Wash Handling
The drying phase is the most sensitive part of the process, as the introduced moisture creates a significant risk of mold and mildew. Immediately after the final rinse, the washed branches must be hung individually, ensuring they are not touching, to maximize airflow around each bud. The drying environment requires constant, high airflow, often achieved with multiple fans, to rapidly remove surface moisture. Controlled environmental conditions are necessary to prevent fungal proliferation. Because the buds are saturated, the drying time will be longer than for unwashed cannabis, requiring close monitoring.