The amount of dried flower, or “bud,” a single cannabis plant produces is highly variable. Bud refers to the dense, resinous inflorescence of the mature female plant, which is the desired final product. Yield is determined by an interplay of genetic inheritance and the specific cultivation environment. For example, a plant grown indoors will yield dramatically less than an identical plant grown outdoors in an optimal climate.
How Yield is Measured and Reported
Growers quantify efficiency using metrics that vary based on the cultivation method. Indoor environments primarily use grams per watt (g/W) of light power or grams per square meter (\(\text{g/m}^2\)) of canopy space. A novice grower might achieve \(0.5 \text{ g/W}\), while commercial operations often target \(1.0 \text{ g/W}\) or higher.
Yield per square meter is a standardized efficiency measure, with many indoor setups aiming for \(400 \text{ to } 500 \text{ g/m}^2\) of dried flower. This metric measures the total output of the grow space, regardless of the number of plants used. Outdoor and large-scale cultivators typically measure yield in grams per plant, which can range widely from \(400 \text{ to } 750\) grams for a single, large plant, sometimes exceeding one kilogram.
The Role of Genetics in Potential Yield
The plant’s biological blueprint establishes its maximum yield potential, dictating its size, structure, and flowering timeline. Indica-dominant strains are typically shorter and bushier, producing dense, heavy buds. This compact morphology is efficient for indoor cultivation where space management is a primary concern.
Sativa-dominant strains grow taller and more lanky, featuring longer spacing between nodes and looser floral structures that require a longer flowering period. While Sativa plants can reach immense sizes outdoors, their structure often results in lower final weight in controlled indoor spaces.
The choice between photoperiod and autoflowering varieties also limits potential size. Photoperiod plants remain vegetative until the light cycle is reduced, allowing growers to cultivate massive plants capable of high yields. Autoflowering plants automatically transition to flowering based on age, resulting in a short life cycle of eight to twelve weeks. This rapid, fixed timeline and smaller stature inherently limit the total floral mass, making their yield significantly lower than photoperiod plants.
Cultivation Factors That Determine Final Weight
The maximum output determined by genetics is only realized through precise management of the growing environment. Light intensity is the single largest controllable factor, as the final dry weight is directly proportional to the total light energy the plant receives, known as the Daily Light Integral (DLI). Studies confirm that increasing light power directly translates to increased floral mass, with dry weight increasing linearly with light intensity (PPFD) up to \(1,000 \text{ µmol/m}^2\text{/s}\) or more.
The quality of light, or the spectrum, also impacts floral development. Red light (\(600 \text{ to } 700 \text{ nm}\)) is highly effective for photosynthesis and linked to increased flowering. Blue light (\(420 \text{ to } 450 \text{ nm}\)) encourages a short, bushy vegetative structure, but a spectrum richer in red light is employed to maximize bud production during flowering.
Nutrient Management
Nutrient management, particularly the balance of primary macronutrients (nitrogen, phosphorus, and potassium), is essential. During the vegetative phase, a high ratio of nitrogen supports leaf and stem growth, building the structure for the final yield. As the plant transitions to flowering, metabolic demands shift, requiring a significant reduction in nitrogen and an increase in phosphorus and potassium. Phosphorus drives the development of dense, heavy buds, while potassium regulates water movement and enzyme activation necessary for bud density.
Space and Training Techniques
The physical space allocated to the roots sets a hard limit on the plant’s final size and yield. The root system determines the capacity for water and nutrient uptake, and the above-ground biomass grows only to the size the roots can support. Cultivating in a container that is too small prevents the plant from reaching its full potential, causing it to become “root-bound” and restricting growth. Techniques like topping, which encourages lateral branching, and Screen of Green (SCROG), which spreads the canopy horizontally, are employed to maximize light exposure and utilize available space to produce a heavier yield.
Understanding Dry Weight vs. Wet Weight
When harvested, the initial measurement is the wet weight, which includes the water content within the fresh floral material. This figure is not representative of the final usable product because cannabis buds are primarily composed of water. The final, consumable yield is always reported as the dry weight, which is the mass remaining after the drying and curing process removes most moisture.
During the drying phase, buds lose a substantial amount of mass, typically between \(70\%\) and \(80\%\) of the initial wet weight. Therefore, the final dry weight of the usable bud is approximately \(20\%\) to \(30\%\) of the weight recorded at harvest. This reduction must be factored in when calculating the true output of a single plant.