Why Defoliate Weed Plants: Light, Air, and Timing
Defoliation opens a cannabis canopy to light and air, but over-stripping hurts yield. Use selective thinning and timing.
How Much to Defoliate Cannabis Leaves
Remove 10% to 20% of fan leaves per session. In flower, remove 20% to 30% at day 21 and day 42. Never remove more than 30% of total leaves at one time. Defoliation above 30% causes shock and yield loss.
defoliation for increasing yields cannabis
Vegetative Stage
Remove 10% to 15% of fan leaves every 2 to 3 weeks. Target leaves in the lower third of the plant. These leaves receive less than 100 PPFD. Keep all leaves on the top two nodes.
Top and Defoliate Cannabis Schedule: Best Plan and 3 Alternatives
Flowering Stage
Week 3 of flower: remove 20% to 30% of fan leaves. Week 6: remove another 20%. Do not defoliate after week 7. Sugar leaves on buds stay. Fan leaves on main colas stay.
Which Leaves to Remove
- Leaves that block light to bud sites.
- Leaves touching soil or mulch.
- Yellow leaves and leaves with pest damage.
- Lower third of the plant.
Which Leaves to Keep
- Sugar leaves on flowers.
- Top 2 to 3 sets of fan leaves.
- Leaves on main colas.
Risks of Too Much Defoliation
More than 30% at once causes shock. Growth stops for 3 to 7 days. Yield drops 10% to 20%. Stress can produce hermaphrodites. Defoliation removes stored energy. Leaves make sugar for buds.
Tools and Method
Use clean scissors. Wipe blades with 70% isopropyl alcohol. Pinch the petiole. Cut at the base. Do not tear. Tearing damages stem tissue.
After Defoliation
Lower humidity to 40% to 50%. Increase airflow. Keep temperature at 75 to 80 F. Wait 2 days before the next session. Check for stress signs: drooping, curling, or slowed growth.