Cannabis Harvest Calculator

When should you harvest cannabis? Enter the date your plant started flowering (the 12/12 flip for photoperiod, or sprout date for autoflowers) and its flowering time to get an estimated harvest date, when to start flushing, and how many days are left. Photoperiod strains flower for 7–12 weeks; autoflowers finish the whole cycle in 8–14 weeks. Confirm the final cut with a trichome check: clear means wait, cloudy/milky means peak THC, amber means a more sedative effect. Most growers harvest at mostly-cloudy with 10–20% amber trichomes.

Frequently Asked Questions

How do I calculate when to harvest cannabis?

Add the strain’s flowering time to the date it started flowering (the 12/12 flip for photoperiod plants, or sprout date for autoflowers). Most photoperiod strains flower 8–10 weeks. Confirm with a trichome check before cutting.

How long does cannabis flowering take?

Photoperiod strains flower 7–12 weeks after switching to 12/12; indica-leaning finish faster, sativa-leaning take longer. Autoflowers finish seed-to-harvest in about 8–14 weeks.

When should I flush before harvest?

Start flushing with plain pH’d water about 1–2 weeks before harvest in soil or coco (3–5 days in hydro) so the final flower burns cleaner.

How do I know cannabis is ready to harvest?

Check trichomes under a loupe: clear means wait, cloudy/milky means peak THC, amber means a more sedative body effect. Most harvest at mostly cloudy with 10–20% amber.

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