# When is outdoor cannabis ready to harvest?

> Outdoor cannabis is ready when its trichomes are mostly cloudy with some amber (roughly 5–20%), which at 35–50° latitude usually falls between mid-September and late October in the Northern Hemisphere and between March and April in the Southern. Early cultivars finish first; late tropical lines run into November or May. Weather can overrule the trichomes: harvest ahead of long rain spells or a hard freeze.

- Canonical: https://genetixbay.com/knowledge/answers/when-to-harvest-outdoors.html
- Topic: Outdoor growing · Type: Numbers
- Evidence: Grower practice · Status: Draft: awaiting expert review
- Full article: [Trichome ripeness: clear, cloudy, amber, and what the evidence says](https://genetixbay.com/knowledge/harvest-cure/trichome-ripeness.md)
- Also asked as: Outdoor harvest time | Is October harvest normal for outdoor cannabis? | Outdoor finish date | When to harvest outdoor plants in the southern hemisphere | Should I harvest early because of rain or frost?
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Short answer

Outdoor cannabis is ready when [calyx](https://genetixbay.com/knowledge/glossary/calyx.md) [trichomes](https://genetixbay.com/knowledge/glossary/trichome.md) are mostly cloudy with some amber, roughly 5–20%. At 35–50° latitude that is usually mid-September to late October in the Northern Hemisphere and March to April in the Southern. Cloudy versus amber is a matter of preference (house position). *Grower practice*, and the weather can overrule it.

## Why

Plants ripen at their own pace. Trichome maturation differs by [genotype](https://genetixbay.com/knowledge/glossary/genotype.md) and plant age, and heads on one [bract](https://genetixbay.com/knowledge/glossary/bract.md) mature unevenly [1].

[Cannabinoids](https://genetixbay.com/knowledge/glossary/cannabinoid.md) plateau, then fall. In [hemp](https://genetixbay.com/knowledge/glossary/hemp.md), totals peaked about 6–7 weeks after flowering began, then declined with [senescence](https://genetixbay.com/knowledge/glossary/senescence.md) [2]. Leaving plants "for more amber" past the plateau costs quality.

Autumn weather is the outdoor grower's real deadline. Gray mould ([botrytis](https://genetixbay.com/knowledge/glossary/botrytis.md)) thrives in cool, wet weather and dense flowers [3], and bud rot is the main late-season outdoor loss [4].

The calendar follows the flowering date. Plants that set flower in mid-August and carry an 8–10 week cultivar, plus the 10–14 day transition, finish in mid to late October.

## The numbers

| Cultivar type | Northern Hemisphere (35–50°) | Southern Hemisphere (35–50°) |
|---|---|---|
| Early outdoor lines, [autoflowers](https://genetixbay.com/knowledge/glossary/autoflower.md) | Late August–late September | Late February–late March |
| Typical drug-type [photoperiods](https://genetixbay.com/knowledge/glossary/photoperiod.md) | Late September–late October | Late March–late April |
| Late, tropical-leaning lines | November or later | May or later |
| Trichome target | Mostly cloudy, ~5–20% amber, a few clear | Same |

## What to do

1. Note when [pistils](https://genetixbay.com/knowledge/glossary/pistil.md) first showed; count the cultivar's weeks from then.
2. From two weeks before the expected date, check calyx trichomes at the top, middle and bottom with a 60–100x [loupe](https://genetixbay.com/knowledge/glossary/jewelers-loupe.md).
3. Keep feeding; [taper nitrogen](https://genetixbay.com/knowledge/glossary/nitrogen-taper.md) in the final weeks rather than [flushing](https://genetixbay.com/knowledge/glossary/flushing.md).
4. Watch the 10-day forecast. Harvest near-ripe plants before long rain or a hard freeze.
5. After rain, shake [colas](https://genetixbay.com/knowledge/glossary/cola.md) dry and open the biggest ones to check for grey mould.
6. Harvest the ripest [tops](https://genetixbay.com/knowledge/glossary/top-shelf.md) first if lower buds lag.

## Common mistakes

- Leaving plants through a week of rain for a few more amber heads.
- Reading sugar-leaf trichomes, which amber early.
- Pre-harvest flushing, a *Myth* that starves the plant at its most important stage.
- Choosing a 12-week cultivar where first frost comes in early October.

## Related

- Full article: [Trichome ripeness: clear, cloudy, amber, and what the evidence says](https://genetixbay.com/knowledge/harvest-cure/trichome-ripeness.md)
- Answers: [How to check trichomes](https://genetixbay.com/knowledge/answers/how-to-check-trichomes.md) · [When outdoor plants flower](https://genetixbay.com/knowledge/answers/when-do-outdoor-plants-flower.md) · [Harvesting too early or late](https://genetixbay.com/knowledge/answers/harvesting-too-early-or-late.md)
- Articles: [Botrytis bud rot](https://genetixbay.com/knowledge/diseases/botrytis-bud-rot.md) · [The flush debate](https://genetixbay.com/knowledge/harvest-cure/flush-debate.md)
- Terms: [outdoor growing](https://genetixbay.com/knowledge/glossary/outdoor-growing.md)

## Follow-up questions

**Should I harvest early because of rain?** Harvest outdoor cannabis early ahead of a long spell of cool, wet weather if the buds are close to ripe, because rain soaking dense colas drives bud rot and can lose more than the last few days of ripening would gain. A short shower followed by sun and wind is usually survivable. Shake water off after rain and inspect the inside of the biggest colas for grey mould.

**Will frost kill my outdoor plants before harvest?** A light frost often damages only exposed leaves on mature outdoor cannabis, but a hard freeze kills the plant and ends ripening, and frozen, thawed buds rot fast. If a hard freeze is forecast and the buds are near ready, harvest beforehand. Covering plants overnight with frost cloth can buy a few nights. Choose cultivars that finish before your usual first frost.

**Should I flush or put outdoor plants in darkness before harvest?** No. Pre-harvest flushing is a myth that starves the plant while it is still packing on weight and resin, so keep feeding at stage strength, tapering nitrogen in the final weeks. Darkness before harvest is a myth too, and impossible outdoors anyway. Judge ripeness by calyx trichomes, swollen calyxes and receded pistils, and let the weather set the final day.

## Sources

1. Punja ZK, Sutton DB, Kim T, 2023. Glandular trichome development, morphology, and maturation are influenced by plant age and genotype in high THC-containing cannabis (Cannabis sativa L.) inflorescences. Journal of Cannabis Research 5:12. https://doi.org/10.1186/s42238-023-00178-9
2. Yang R, Berthold EC, McCurdy CR, et al., 2020. Development of cannabinoids in flowers of industrial hemp (Cannabis sativa L.): a pilot study. Journal of Agricultural and Food Chemistry. https://pubmed.ncbi.nlm.nih.gov/32392412/
3. PNW Plant Disease Management Handbook. Hemp (Cannabis sativa) - Gray Mold. https://pnwhandbooks.org/plantdisease/host-disease/hemp-cannabis-sativa-gray-mold-botrytis-bud-blight-stem-canker
4. Utah State University Extension. Hemp bud rot (IPM Notes). https://extension.usu.edu/planthealth/ipm/notes_ag/hemp-bud-rot