Single-bladed, round or smooth-edged new leaves
Appears weeks into flower or after harvest-and-regrow; new shoots with 1-3 smooth leaflets from the buds..
- Also called
- single finger leaves
- round leaves
- reveg leaves
- mutant leaves
- leaves with no serrations
Likely causes, most likely first
Ranked for this sign on its own. Your stage, medium and readings change the order, so run the checker for your plant.
PossibleLight leak or interrupted dark period
Fix: Seal the dark period: pinholes, zips, vents and equipment LEDs (tape them), and check the timer. Even dim night light can delay flowering in sensitive cultivars and reveal herm-prone genetics. Use a green headlamp only for brief checks.
Recovery: Flowering resumes within 1-2 weeks; no new single-blade leaves.
How to confirm it
- Check for light leaks in the dark period. Sit inside the tent or room for 5 minutes after lights-off until your eyes adjust. Look for pinholes, zips, vents, indicator LEDs on equipment and light under doors. Also confirm the timer actually switches off and stays off.
PossibleRe-vegetation from too-long days in flower
Fix: Restore an uninterrupted 12-13 h dark period (13/11 is fine; some cultivars flower at 14-15 h days with ramps). Outdoors, early-season plants under long days re-veg; plant later or use light deprivation.
Recovery: No new single-blade growth within 2 weeks.
How to confirm it
- Check for light leaks in the dark period. Sit inside the tent or room for 5 minutes after lights-off until your eyes adjust. Look for pinholes, zips, vents, indicator LEDs on equipment and light under doors. Also confirm the timer actually switches off and stays off.
Look for
Odd, roundish single-blade leaves growing out of bud sites or tips..
The full guide: Why is my plant growing single-finger leaves?
Guidance, not a guarantee. The checker weighs common causes against what you tell it; confirm with the tests before you treat, change one thing at a time and watch the new growth.
