A fast-growing species of marijuana originating in northern Central Asia and Siberia. Contrast cannabis sativa, cannabis indica.

Only weakly psychoactive, ruderalis is primarily noted for reaching maturity based on age rather than photoperiod, meaning that it flowers after a certain number of weeks rather than when the days shorten. Depending on germination date, this can produce a shorter growing season and thus, theoretically, a greater annual yield.

In practice, poor THC quality more than offsets the shorter season. Nevertheless, ambitious growers at the Super Sativa Seed Club in the Netherlands (and elsewhere) have married ruderalis with more potent varieties to produce strains such as Early Girl, Early Pearl and Early Skunk.