When to Harvest Cannabis: Reading Trichomes
Harvesting at the right time is the difference between good weed and great weed. Harvest too early and you lose potency; too late and THC degrades into sleepy CBN. Learn to read trichomes like a pro.
Quick Answer: When to Harvest
Harvest cannabis when: 70-90% of pistils (white hairs) have turned brown/orange, AND trichomes are mostly cloudy/milky with 10-30% amber. Use a 30x-60x jeweler's loupe to check trichomes. Flush with plain water for 1-2 weeks before chopping.
In This Guide
Why Harvest Timing Matters
After weeks of careful growing through germination, seedling, veg, and flowering, don't ruin your harvest by chopping at the wrong time!
Harvest too early:
- Lower THC content (cannabinoids not fully developed)
- Racy, anxious, potentially paranoid high
- Less weight (buds haven't fully swelled)
- Underdeveloped terpene profile (less flavor/aroma)
Harvest too late:
- THC degrades into CBN (sedative, "couch-lock" effect)
- Heavy, sleepy high instead of euphoric
- Potential for bud rot if humidity rises
- Terpenes can degrade, reducing flavor
Did You Know? THC naturally degrades into CBN (cannabinol) over time when exposed to oxygen and light. This is why properly cured cannabis stored in dark, airtight containers maintains potency longer. CBN is mildly psychoactive and known for sedative properties.
Method 1: The Pistil Method (Good)
The easiest way to gauge harvest readiness is by observing the pistils—the white hair-like structures on buds. As the plant matures, pistils darken from white to orange, red, or brown and curl inward.
| Pistil Color | Percentage Brown | Readiness |
|---|---|---|
| Mostly White | 0-49% | Too Early |
| Half & Half | 50-69% | Getting Close |
| Mostly Brown/Orange | 70-90% | Harvest Window |
| All Brown, Shriveled | 90-100% | Past Peak (Harvest Now) |
Limitation: The pistil method is a rough estimate. Different strains have different pistil behaviors, and some produce new white pistils late into flowering. For precision, combine this with the trichome method.
Method 2: The Trichome Method (Best)
For precise harvest timing, you need to examine the trichomes—the tiny mushroom-shaped resin glands covering buds and sugar leaves. This requires magnification (30x-60x jeweler's loupe or USB microscope).
Focus on trichomes on the buds themselves, not sugar leaves (leaves mature faster and aren't representative).
Trichome Color Guide
- Clear/Glassy: Not ready. Cannabinoids are still developing. Harvesting now produces weak, racy effects.
- Cloudy/Milky: Peak THC content. Most energetic, euphoric, cerebral high. This is the optimal window for many growers.
- Amber: THC is converting to CBN. More body-heavy, sedative, "couch-lock" effect. Good for nighttime/medical use.
Recommended harvest window: 70-80% cloudy with 20-30% amber for balanced effects. More amber = more sedative; less amber = more energetic.
Flushing Before Harvest
Flushing means feeding your plants only plain, pH'd water (no nutrients) for the final 1-2 weeks before harvest. The goal is to force the plant to use up stored nutrients in its tissues.
Benefits of flushing:
- Smoother smoke (less harshness)
- White ash when burned (vs. black ash from nutrient buildup)
- Cleaner flavor (terpenes shine through)
- Reduced chemical taste
Note: Flushing is Debated
Some studies suggest flushing doesn't significantly affect final nutrient content in flowers. However, most experienced growers report improved taste after flushing. When in doubt, flush—it won't hurt and may help.
48 Hours of Darkness (Optional)
A popular technique is giving plants 48-72 hours of complete darkness before chopping. The theory: stressed plants produce a final burst of resin as a protective response. While not scientifically proven, many growers report increased trichome production.
How to Harvest: Step-by-Step
- Stop watering 1-2 days before harvest. Slightly dry soil speeds up drying.
- Optional: Give 48 hours of darkness.
- Cut the plant at the base of the main stem, or cut individual branches.
- Trim immediately (wet trim) or hang whole plant and trim later (dry trim).
- Hang to dry in a dark room at 60-70°F and 55-65% humidity for 7-14 days.
- Begin curing once stems snap (not bend). See our Drying & Curing Guide.
Wet Trim vs. Dry Trim
- Wet Trim: Trim sugar leaves immediately after cutting while plant is still wet. Easier to trim, faster drying, but some argue it reduces flavor.
- Dry Trim: Hang whole plant with leaves, trim after drying. Slower dry (better for humid climates), preserves terpenes, but more tedious trimming.
Frequently Asked Questions
When is cannabis ready to harvest?
Harvest when 70-90% of pistils are brown AND trichomes are mostly cloudy/milky with 10-30% amber. Use a 30x-60x loupe to check trichomes on the buds (not leaves). This typically occurs 8-12 weeks into flowering.
What do trichome colors mean?
Clear = not ready, low potency. Cloudy/milky = peak THC, energetic high. Amber = THC converting to CBN, sedative/couch-lock effect. Harvest at 70-80% cloudy + 20-30% amber for balanced effects.
Should I flush before harvest?
Most growers recommend flushing with plain pH'd water for 1-2 weeks before harvest. This is believed to remove residual nutrients, resulting in smoother smoke and better flavor. It's a low-risk practice.
What is 48-hour darkness before harvest?
Some growers give plants 48-72 hours of total darkness before chopping, believing it causes a final surge of trichome production. While not scientifically proven, many report positive results. It's optional.
How do I know if I harvested too early?
Signs of early harvest: mostly clear trichomes, white pistils, lower potency, racy/anxious high, and less weight than expected. The high tends to be more paranoid and less enjoyable.
Can I harvest cannabis in stages?
Yes! Staggered harvesting is common. Top colas get more light and mature faster—harvest them first, then let lower buds ripen for another 1-2 weeks. This maximizes total yield and potency.
Fast-Finishing Strains
Can't wait? These strains race to harvest with short flowering times:
Continue Growing
Ready for Your Next Grow?
Premium cannabis seeds with proven genetics. Every order ships free with bonus seeds.
Shop Cannabis Seeds