Cannabis Flowering Stages Week by Week (With Pictures)

When your cannabis plant flips to a 12/12 light schedule (or hits maturity if you're running autoflowers), the flowering stage begins. For the next 8-10 weeks, your plant transforms from a leafy bush into a resinous, bud-covered producer. Knowing exactly what each week should look like is the difference between harvesting at peak potency and cutting too early or too late.

This guide uses real flowering photos and data from documented grow journals on Grow Guide — including GrowWithGozen's Perpetual Autoflower Mixed Grow (Lemon Cherry Gelato, Event Horizon, Lord of the Runtz), 59XoticsGrow's Celestial Blueberry (greenhouse photoperiod, 110g/plant harvest), and OG_CPT_ZA's Amnesia Haze Run (indoor coco/perlite hydro). These are real plants tracked day by day, not stock photos.

Week 1 of Flowering: The Transition and Stretch

The first week of flowering doesn't look like flowering at all. After flipping to 12/12 (or around days 25-35 for autoflowers), your plant enters the "stretch" — a burst of vertical growth that can add 50-100% to the plant's height over 1-2 weeks. In OG_CPT_ZA's Amnesia Haze grow, the plants showed aggressive stretching starting around day 28 as they transitioned into flower.

What to expect visually at 1 week into flowering

• Rapid vertical growth — internodes stretching apart
• New growth at every node, branches reaching upward
• No visible pistils or buds yet on most strains
• Lighter green new growth at the tops

Key metrics — Week 1

• PPFD: 600-800 µmol/m²/s (use our grow light calculator to dial this in)
• VPD: 1.0-1.2 kPa
• EC: 1.2-1.6 (still in transition feed — moderate nitrogen)
• pH: 6.0-6.5 (soil) / 5.8-6.0 (hydro/coco)

Common actions at this stage

• Final defoliation or tucking of fan leaves to open canopy
• Last round of low-stress training (LST) to even out the canopy
• Begin transitioning nutrients from veg to bloom formula (50/50 mix this week)
• Raise lights if stretch is outpacing your headroom

What can go wrong

The stretch catches new growers off guard. If you don't have 30-50 cm of headroom above your canopy, plants will grow into the light and burn. This is also when hidden males reveal themselves on regular seeds — check every node daily for pollen sacs vs. pistils.

2 Weeks Into Flowering (With Pictures)

By the end of week 2, the stretch slows and you'll see the first unmistakable sign of flowering: white pistils (hairs) emerging at the nodes. In GrowWithGozen's autoflower grow, the Lemon Cherry Gelato and Event Horizon plants showed clear pistil development around days 51-55, with the stretch phase winding down.

What to expect visually at 2 weeks into flowering

• White pistils (hairs) appearing at nodes and branch tips
• Stretch slowing but not fully stopped
• Pre-flower sites visible — small clusters of pistils at each node
• Increased resin production on sugar leaves near tops

Key metrics — Week 2

• PPFD: 700-900 µmol/m²/s
• VPD: 1.0-1.3 kPa
• EC: 1.4-1.8 (shifting to bloom-heavy nutrients)
• Humidity: Drop to 50-55% — bud rot prevention starts now

Common actions at this stage

• Switch fully to bloom nutrients (higher P and K, lower N)
• Remove any remaining lower growth that won't reach the canopy (lollipop)
• Ensure good airflow between and around developing bud sites

What can go wrong

Continuing high-nitrogen veg feeds into week 2 causes "nitrogen claw" — dark green, downward-curling leaves that slow bud development. Make the nutrient switch. Also watch for calcium and magnesium deficiency (brown spots on middle leaves) — bloom nutrients often have less cal-mag than veg formulas. Use our nutrient deficiency identifier if you're seeing spots or discoloration.

3 Weeks Into Flowering (With Pictures)

Week 3 is where flowering gets exciting. The stretch stops, and energy redirects into bud production. Small but definite bud clusters form at every node, and the main colas begin taking shape. Based on grow journals tracked on Grow Guide, week 3 is when most growers see the first real "bud structure" — not just pistils, but actual calyx clusters stacking up.

In 59XoticsGrow's Celestial Blueberry grow, the photoperiod plants showed clear bud formation by flowering day 25-30, with small but structured colas developing under greenhouse conditions in soil.

What to expect visually at 3 weeks into flowering

• Small bud clusters forming at the top of each branch
• Pistils multiplying and growing longer
• Stretch fully stopped — plant height is now set
• Trichomes beginning to appear on sugar leaves (may need a loupe to see)
• First hints of strain-specific smell developing

Key metrics — Week 3

• PPFD: 800-1,000 µmol/m²/s
• VPD: 1.2-1.4 kPa
• EC: 1.6-2.0 (plants are now hungry for phosphorus and potassium)
• Humidity: 45-55%

Common actions at this stage

• Full bloom nutrient strength — do not hold back on P and K
• Selective defoliation of large fan leaves blocking bud sites (remove no more than 20% of foliage at once)
• Start monitoring trichome development with a jeweler's loupe or digital microscope

What can go wrong

Light stress and heat stress at week 3 cause "foxtailing" later — buds that grow in loose, spire-like shapes instead of dense nugs. Keep canopy temperatures below 28°C (82°F) and maintain proper light distance. This is also when mold and powdery mildew become a risk if humidity is above 60%.

4 Weeks Into Flowering (With Pictures)

Four weeks into flowering is when the magic is unmistakable. Buds are fattening daily, pistils are dense and white, and the smell is getting strong. This is the stage most growers photograph — the buds are recognizable but still have weeks of growth ahead. Based on grow journals tracked on Grow Guide, plants typically put on 40-60% of their final bud mass between weeks 4-6.

In GrowWithGozen's grow, the Lord of the Runtz and Lemon Cherry Gelato plants showed rapid bud development around days 65-70, with dense flower clusters stacking at every node. OG_CPT_ZA's Amnesia Haze clones were similarly packing on weight in coco/perlite around day 42-48 of flower.

What to expect visually at 4 weeks into flowering

• Buds noticeably larger — individual calyxes visible to the naked eye
• Pistils thick and mostly white, standing straight up
• Trichomes visible without magnification on sugar leaves
• Strong terpene smell — carbon filter earning its keep
• Lower fan leaves may start yellowing slightly (normal nitrogen redistribution)

Key metrics — Week 4

• PPFD: 900-1,100 µmol/m²/s (peak light intensity if your plants handle it)
• VPD: 1.2-1.5 kPa
• EC: 1.8-2.2 (peak feeding for most strains)
• Humidity: 45-50%

Common actions at this stage

• Peak nutrient feeding — plants are consuming heavily
• Consider adding a PK booster (extra phosphorus and potassium) if your base nutrients don't already include high P-K ratios
• Support heavy branches with plant stakes or a trellis net if buds are weighing them down
• Check the yield calculator to estimate your final harvest weight based on plant count and light wattage

What can go wrong

Nutrient burn is common at week 4 because growers push feeding too hard when they see rapid bud growth. Watch for brown, crispy leaf tips — if you see them, back off EC by 0.2-0.3. Also, bud rot (botrytis) can start inside dense colas at this stage if humidity spikes above 55% overnight. Check the inside of your largest buds regularly.

5 Weeks Into Flowering (With Pictures)

At 5 weeks into flowering, the buds are entering their heaviest growth phase. Calyxes swell noticeably, trichomes coat the sugar leaves in a frosty layer, and pistils begin to look crowded as new ones push out between established ones. In 59XoticsGrow's Celestial Blueberry, this mid-flower stage showed impressive calyx development under greenhouse light — the kind of density that ultimately led to the 110g per plant harvest.

What to expect visually at 5 weeks into flowering

• Calyxes swelling — buds look "stacked" with rounded structures
• Trichome coverage obvious on buds and surrounding sugar leaves
• Under magnification, trichomes are mostly clear to slightly cloudy
• Some of the earliest pistils may start turning orange/brown at the base
• Pungent smell — even with carbon filtration, the room smells when you open it

Key metrics — Week 5

• PPFD: 900-1,100 µmol/m²/s
• VPD: 1.2-1.5 kPa
• EC: 1.6-2.0 (begin tapering slightly from peak)
• Humidity: 40-50%

Common actions at this stage

• Maintain peak feeding but watch for signs of overfeeding
• Remove any dead or dying fan leaves — they're entry points for mold
• Continue checking trichomes with a loupe — you're establishing a baseline for the ripening window
• Some growers do a final light defoliation at day 35-42 to expose lower bud sites to direct light

What can go wrong

Potassium deficiency shows up at week 5 more than any other stage — brown, crispy edges on fan leaves that progresses inward. Don't confuse this with nutrient burn (which affects leaf tips only). Potassium is consumed heavily during bud building. Also, light leaks during the dark period can cause hermaphrodite stress (pollen sacs on a female plant), especially in photoperiod strains. Check your tent or room for pinholes of light.

6 Weeks Into Flowering (With Pictures)

Six weeks into flowering is often the visual peak — buds are dense, covered in trichomes, and the first pistils are changing from white to orange or brown. The plant knows it's approaching maturity. In GrowWithGozen's autoflower grow, the Event Horizon and Lemon Cherry Gelato plants around days 80-85 showed exactly this pattern: heavy, frosty buds with pistils just beginning their color shift.

OG_CPT_ZA's Amnesia Haze at around day 56-60 of flower showed similar maturation in the coco/perlite system, with buds stacking dense and trichome production accelerating.

What to expect visually at 6 weeks into flowering

• Buds are dense and heavy — branches may need support
• 30-50% of pistils turning orange/brown
• Trichomes shifting from clear to milky/cloudy under magnification
• Fan leaves yellowing and dropping — this is normal at this stage
• Sugar leaves curling slightly inward around buds

Key metrics — Week 6

• PPFD: 800-1,000 µmol/m²/s (some growers reduce slightly as harvest approaches)
• VPD: 1.2-1.5 kPa
• EC: 1.2-1.6 (begin reducing feed — some growers start flushing at week 6 for 8-week strains)
• Humidity: 40-45% — keep it low, dense buds trap moisture

Common actions at this stage

• Start reducing nutrient concentration if harvesting in 2 weeks
• For strains that run 9-10+ weeks, maintain full feeding
• Increase airflow — oscillating fans and exhaust are critical now
• Check trichomes every 2-3 days — things change fast from here

What can go wrong

Bud rot (botrytis) is the number-one threat at week 6. Dense buds with poor airflow and humidity above 50% are a recipe for disaster. If you see a brown, mushy spot inside a cola, remove it immediately — cut 2-3 cm below the affected area, and sterilize your scissors. Check surrounding buds. One rotten cola can spread to the entire plant in 48 hours if undetected.

Week 7 of Flowering: Ripening Begins

Week 7 is the beginning of the end. Most 8-week strains are now in their ripening phase. Bud growth slows, but trichomes continue to mature, and the final terpene profile locks in. In 59XoticsGrow's Celestial Blueberry, the final weeks of flowering (around day 55-60 of flower) showed the classic late-stage ripening: pistils mostly darkened, fan leaves yellowing and dropping, and trichomes shifting from milky to the first hints of amber.

What to expect visually at 7 weeks into flowering

• Bud growth slowing — the plant is redirecting energy to resin production
• 60-80% of pistils orange/brown, curling inward toward the buds
• Trichomes mostly milky/cloudy with a few clear and a few amber
• Fan leaves yellowing rapidly — the plant is consuming stored nutrients
• Smell peaks — the full terpene profile is expressing

Key metrics — Week 7

• PPFD: 700-900 µmol/m²/s
• VPD: 1.0-1.3 kPa
• EC: 0.4-0.8 (flushing with plain pH'd water, or very light feed)
• Humidity: 35-45%

Common actions at this stage

• Most growers begin flushing — feeding only plain, pH'd water for the final 7-14 days
• Remove large dying fan leaves to improve airflow and reduce humidity pockets
• Some growers reduce light hours to 11/13 or 10/14 in the final 1-2 weeks to encourage ripening (more common with sativa-dominant strains)
• Set up your drying space — you'll need it in 1-2 weeks. Use our dry and cure timer to plan your post-harvest workflow

What can go wrong

Harvesting too early is the most common mistake at week 7. Growers see orange pistils and yellowing leaves and panic — thinking the plant is dying. It's not. Those are signs of natural maturity. Trust the trichomes, not the pistils. Clear trichomes = too early. You want milky with some amber.

8 Weeks Into Flowering and Beyond: The Harvest Window

Week 8 is harvest week for many indica-dominant and autoflower strains. Sativa-dominant strains like Amnesia Haze may run 10-12 weeks in flower. The key is not the calendar — it's the trichomes. Based on grow journals tracked on Grow Guide, the most common harvest window falls between days 56-70 of flower for indica/hybrid strains, and days 70-84 for sativa-dominant genetics.

GrowWithGozen's autoflower grow documented harvest across days 100-109 from seed, with different strains finishing at slightly different times. 59XoticsGrow's Celestial Blueberry went to harvest around day 85 of flower, yielding 110g per plant in soil.

What to expect visually at 8 weeks into flowering

• 80-90% of pistils darkened and curled into the buds
• Trichomes: 70-80% milky, 10-20% amber, few clear remaining
• Buds feel firm and dense when gently squeezed
• Most fan leaves yellow or dropped — the plant looks "used up"
• Some strains show purple, red, or dark coloring in the final week (anthocyanin expression, especially with cooler night temperatures)

The trichome harvest guide

Use a jeweler's loupe (60x-100x) or a USB digital microscope to check trichomes on the buds (not the sugar leaves — those amber faster and give a misleading read):

• All clear: Too early. THC hasn't peaked. Wait.
• Mostly milky/cloudy, few amber: Peak THC. Energetic, cerebral high. Harvest here for maximum potency.
• 50/50 milky and amber: THC converting to CBN. More sedative, body-heavy effect. Good for evening/medical use.
• Mostly amber: Past peak. CBN dominant. Sleepy, couch-lock effect. Most growers want to harvest before this point.

Common actions at harvest

• 48 hours of darkness before chop (debated, but many growers swear by it for trichome production)
• Whole-plant hang or individual branch drying at 15-18°C (60-65°F) and 55-62% humidity
• Dry for 10-14 days until small stems snap rather than bend
• Cure in glass jars at 58-62% humidity for minimum 2 weeks, ideally 4-8 weeks
• Use the Grow Guide dry and cure timer to track your drying and curing process and hit the right humidity targets

Strains that run longer than 8 weeks

Not all strains finish at week 8. Sativa-dominant genetics and some landrace strains can run 10-14 weeks in flower. OG_CPT_ZA's Amnesia Haze is a good example — this sativa-dominant strain requires patience well beyond the 8-week mark. If your trichomes are still mostly clear at week 8, keep going. The plant will tell you when it's ready.

Quick Reference: Cannabis Flowering Week by Week

How to Know When to Harvest

Forget counting weeks on a calendar. The only reliable harvest indicator is trichome color, viewed under magnification on the bud surface (not sugar leaves). Here's the process:

1. Get a loupe or microscope. A 60x jeweler's loupe costs under $10 and is the single most important harvest tool you own.
2. Check trichomes on buds, not leaves. Sugar leaf trichomes mature faster and will mislead you into harvesting early.
3. Check multiple bud sites. Top colas ripen before lower buds. Some growers harvest in stages — tops first, then let lower buds ripen for another 5-7 days.
4. Look at the trichome heads (the bulbous tops, not the stalks). You want mushroom-shaped gland heads that are milky/cloudy.
5. Target 70-80% milky, 10-20% amber, under 10% clear for a balanced potency and effect profile.

After harvest, the dry and cure process is just as critical as the grow itself. Rushing the dry (under 7 days) or skipping the cure produces harsh, hay-smelling flower regardless of how well you grew it. Plan your dry for 10-14 days at 60°F/60% RH, and cure in jars for at least 2 weeks. Track it with the dry and cure timer.