A gram (g) is the basic unit used to weigh cannabis for sale, dosing and yield records. Grow yields are reported in grams of dry flower, for example "450 g per m²" or "1.2 g per watt".
In practice
Growers compare runs using dry weight in grams after drying and trimming, not wet weight: fresh flower loses roughly 75-80% of its weight as it dries. A plant weighing 500 g wet at chop might give 100-125 g dry. Weigh on a calibrated scale with 0.1 g or 0.01 g resolution for small amounts, and record yield per plant and per square metre so results can be compared between rooms and grows.
Units and formula
| Slang | Nominal weight | Metric |
|---|---|---|
| Gram | 1 g | 1 g |
| Eighth | 1/8 oz | 3.5 g (exact: 3.54 g) |
| Quarter | 1/4 oz | 7 g |
| Half | 1/2 oz | 14 g |
| Ounce (zip, O) | 1 oz | 28 g (exact: 28.35 g) |
| QP | 1/4 lb (4 oz) | 113 g |
| Pound (elbow, LB) | 1 lb (16 oz) | 454 g (exact: 453.6 g) |
Retail rounds an eighth to 3.5 g and an ounce to 28 g.
Don't confuse with
- Gram of concentrate: same weight unit, very different amount of cannabinoid.
- Gram per watt: a lighting efficiency yardstick for yield, not a sales unit.
Yield is the dry weight of usable flower harvested, usually expressed per plant, per square metre of canopy (g/m²) or per watt of light (g/W).The weight of cannabis after drying (and usually trimming), the basis growers use for yield; it is typically about 20-25% of trimmed wet weight.The weight of cannabis freshly cut, before drying; buds typically lose about 70-80% of it, so dry weight is roughly a quarter of wet.A cannabinoid is any compound that binds the body's cannabinoid receptors or shares the typical cannabis terpenophenolic structure; the plant-made ones are phytocannabinoids such as THCA and CBDA.Grams per watt (g/W) is dry flower yield divided by the electrical wattage of the grow lights, a rough measure of how efficiently a grow turns power into product.An eighth is one-eighth of an ounce of cannabis, sold as 3.5 grams; it is the standard retail unit for flower in North America.An ounce of cannabis is 28.35 grams, rounded to 28 g in retail; slang includes zip, O and onion.A QP is a quarter pound of cannabis: 4 ounces, about 113 grams.Elbow is slang for a pound of cannabis, 16 ounces or about 454 grams, from the spoken abbreviation "L-B".
