How Long Does It Take to Grow Cannabis?

Why

For an indoor photoperiod grow from seed, that's a planning estimate, not a rule.

Think of the grow as two clocks.

The first clock is mostly yours.

Once established, you decide how long to keep it under long days before switching to a flowering schedule.

Published indoor studies used long-day periods from about two weeks to several months. One six-month case was an outlier.

So you can switch early, or keep vegging until Jack starts asking about his beanstalk.

A rooted clone starts partway through that clock, so its timeline isn't the same as starting from seed.

The second clock is more the plant's.

After the switch, the calendar is less under your control. Genetics and growing conditions influence how long flowering takes.

So if a breeder lists “nine weeks of flowering,” that does not mean nine weeks from seed.

Check where that flowering clock starts. A light-schedule change and visible flower development are different events, and researchers don't use one universal definition.

Autoflowers are different. They're day-neutral, so they don't wait for you to shorten the light schedule before moving into flowering.

For photoperiod plants, that distinction applies in soil, DWC, or RDWC.

Seed-to-harvest ends at harvest. Drying and curing come afterward.

So when somebody says their grow took ten weeks, ask the question that matters: ten weeks from what, to what?