From seed a quick flower (under 30 day's) is touchy it will work but the plant is not mature enough to produce as high THC % in the trichomes as if it were older when you started to flower. It takes on average 30 day's for all the antioxidants to form and mature.

Clones are a different story all to together, a clone inherits the age of the mother so once they have roots you can flower them.
Zandor Reviewed by Zandor on . minimum dayz 2 force in flower? Hey, quick question, i was just wondering when you can force your plant to flower, like minimum dayz or height? i was on happychappy's grow forum and he forced his on day 21 from seed. Cheerz. Rating: 5