Reaching the final weeks of the blooming period is one of the most exciting moments for any grower. After months of care, your cannabis plants are heavy with resin and closing in on harvest day. However, managing this late flowering stage correctly, from flushing remaining nutrients to reading trichome colors - is what truly dictates the aroma, taste, and final potency of your yield.

How much weight do buds gain in the last weeks of flowering?, it depends on the strain. Also the flowering stage time lapse differs per strain or genetics. They should still be beautifully green and the buds should still be growing, even though the major part of their development has already been completed. Production of THC is now at full speed. The leaves around the buds will become increasingly sticky because of the many THC-rich resin glands that are growing.

What Makes the Final Flowering Weeks a Game-Changer?

• THC Peak: Trichomes shift from clear to milky, packing a punch - nature’s timing is everything.
• Flavor Fine-Tuning: Proper care now shapes that earthy or citrusy kick you’ll savor.
• Bud Density: The right moves can turn soft clusters into rock-hard beauties.
• Stress Relief: Nailing this stage feels as good as the grow itself - trust us!

Your End-of-Flowering Playbook

Weeks 5-7: The Maturation Surge

Around week five, buds swell as pistils thicken into dense colas - outdoors, this hits with shorter days. Strain timing varies: Yellow Lemon Haze might stretch 10-12 weeks, while Critical Jack wraps in 8-9. Grab a 60x loupe - clear trichomes mean wait, milky signals peak potency, amber leans toward a heavier stone. Last season, Grower M harvested 580g of Premium Shiva Skunk at week 7 with this method. Keep temps 20-26°C and humidity under 50% - a small fan saved my damp crop years ago!

Weeks 8-9: The Ripening Rush

Growth slows, but buds mature fast. Pistils turn 70-80% brown - your harvest cue. Snip fan leaves to light up lower buds; dry them for kief if you’re crafty. Boost with PK 13/14 (1-2 ml/L) to harden buds, but ease off if leaves yellow - overfeeding’s a common slip-up. Outdoors, shield from rain with tarps or raised beds. Grower P juiced his Hollands Super Bud with a weekly potassium foliar spray (1:100 dilution), adding noticeable heft.

The Last 10-14 Days: Harvest Precision

Stop nutrients 10-14 days before cutting - flush with pH’d water (6.2-6.5) to rinse salts and enhance flavor. Buds won’t grow more, but trichomes deepen, boosting potency. If humidity climbs above 50%, ventilate with a fan or prop open a space to dodge mold. Harvest when 80% of pistils brown, but test a lower bud early for that uplifting “high” or deeper “stone.” I stretched White Dwarf Auto an extra week once for a couch-lock dream!

Pruning leaves

Now the harvest  is getting closer, it's time to remove the leaves around the buds and the bigger leaves that contain THC. This can also be done later on, but if you do it now, you save time and more light will fall on the lower buds, which allows them to grow a bit more at the last moment. You can dry these leaves to make kief, hash, hash oil or ice hash from it.

Blooming boosters

Because blooming plants need more phosphorus and potassium, you can give them PK 13/14 as an additional stimulant for their growth and flowering. It will make the buds harder and more compact. You can also administer additional products such as blooming stimulators, blooming boosters, and enzymes.

If you are a beginning grower, these products are probably superfluous because they are only of use if everything went well during the growth period. There's a fair chance that you will have made some mistakes if you are a beginning grower. If you are an experienced grower, these products will enhance your harvest.

Final 2 Weeks at a Glance

• Trichome Check: Aim for 70–80% milky/cloudy and 10–20% amber trichomes for peak potency.

• Flushing: Stop giving nutrients 7 to 14 days before harvest; feed with plain, pH-adjusted water (approx. pH 6.0–6.5).

• Humidity: Drop Relative Humidity (RH) to 40–45% to prevent mold and bud rot (Botrytis).

• Temperature: Maintain daytime temperatures between 20°C and 24°C.

Suzy’s Tip:

Try to make sure that the humidity stays below 50% in the last few weeks of the flowering period. If the humidity is too high, this can lead to stone hard buds, which might develop mold in the last weeks of their growth phase. 

If you have discovered mold in a bud, it is as good as lost. Once 80% of the hairs have turned brown, it's time to prepare for the harvest. The ideal temerature during the flowering phase is between 20° and 28° Celsius. You can influence the type of high you get from smoking your cannabis by harvesting the buds a bit sooner or later. The longer you wait, the stronger the 'stone' of the cannabis will be. If you harvest a bit sooner, you get more of a 'high' effect. The harvesting time, therefore, depends on your personal preference.

Beware:

A bud that died or has been infected by mold will also develop brown hairs. You can start harvesting when 80% of the hairs are brown. If most of the buds have brown hairs but a couple of the lower buds still have white hairs, you can still start harvesting. In order to try out the different highs, you can also harvest in phased intervals.

Flushing

Flushing means rinsing the medium in which the cannabis plants are. Growers then flush with water only. By rinsing you remove all nutrients, bacteria and micro life from the medium. Many growers flush in the last cultures of flowering to improve the taste. The plants break down the chlorophyll and convert it into energy. The buds are not growing in size during flush. The plant yellows and dies. That is actually a shame since you deny the plant the necessary nutrients in a crucial phase. Growers that flush too early therefore miss out on yield and quality. Those who do not flush should cure at least 3 weeks. 

Keep in mind that autoflowering strains mature faster. Check our guide on Autoflowering Seeds if you are growing autos, as flushing timelines are slightly compressed.

Outdoor Late-Stage Blooming Considerations

During the final weeks of outdoor flowering, especially as autumn brings cooler night temperatures, morning dew, and unpredictable rain, vigilance is key. Dense, maturing colas become highly susceptible to bud rot (Botrytis) and powdery mildew. Inspect your plants daily by gently opening heavy clusters to check internal stems for any signs of gray discoloration.

To minimize moisture buildup, shake standing water off your plants after morning rain and prune lower yellowing fan leaves to improve airflow through the canopy. If persistent rain or early frost threatens your grow before reaching maximum trichome amber levels, harvesting slightly early will protect your crop and yield from rot losses.

Pro Hacks for the Home Stretch

• Mold Patrol: Clip suspect buds early - mold loves late-season moisture.
• Light Boost: Angle white boards to reflect sun onto lower buds.
• Cure Setup: Prep a dark, 18-20°C spot for 2-3 weeks post-harvest.
• Trichome Timing: Log daily changes - my early grows taught me patience pays off!

Ready to chop? Once your trichomes reach peak maturity, head over to our complete Cannabis Harvest Guide to learn how to trim, dry, and cure your buds.

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