Most cannabis clones root in 7 to 14 days under the right conditions. Some fast-rooting strains push roots in 5 to 7 days. Slower or stressed cuttings can take up to 21 days before you see any growth.
If you tug the cutting gently after day 7 and feel resistance, roots are forming. New leaf growth at the top is another tell. If nothing has happened by day 14, the cutting probably failed.