Banana Pollen Sacs (Nanners): Identification and Handling
How to identify, bag, and remove nanners before they pollinate your crop.
Growing, buying or possessing cannabis and seeds is legal only in some places. Check the law where you live before acting on this information.
Nanners are real and urgent—viable pollen can disperse the moment you see them. Most nanner events are preventable (light leaks, timer faults, heat spikes). Genetics matter, but blaming the seed bank first ignores the obvious. Bagging before cutting is non-negotiable. Spraying water or using silver products after flowering has started won't fix the problem and will waste your time.
What a nanner actually is
A 'nanner' is a single, banana-shaped stamen (the male pollen-bearing organ) that emerges directly from a female flower without the protective calyx-like sac that surrounds normal male pollen sacs. The name comes from its curved yellow or light-green appearance.
Cannabis is normally dioecious—separate male and female plants—but it can express intersex (monoecious) traits under stress or due to genetics Strong evidence[1][2]. There are two visually distinct forms of intersex expression:
- True pollen sacs: round, grape-cluster-shaped structures that develop over days and release pollen on a predictable schedule. These resemble male flowers.
- Nanners: exposed anthers with no sac. They can shed pollen almost immediately upon emergence Strong evidence[2].
That second point is what makes nanners urgent. By the time you see them, viable pollen may already be in the air.
Why nanners appear
Nanners are a stress or genetic response. The most well-documented triggers include:
- Light leaks or interrupted dark periods during flower Strong evidence[1]. Even a brief light breach during the dark cycle can trigger intersex expression.
- Heat stress above roughly 30 °C / 86 °F at the canopy Weak / limited.
- Late harvest — plants past peak ripeness often throw nanners as a final self-pollination strategy Weak / limited[1].
- Physical damage, severe defoliation, or root problems late in flower Weak / limited.
- Unstable genetics — some cultivars are prone to intersex expression across multiple grows under otherwise clean conditions Strong evidence[1][2].
The popular claim that 'feminized seeds always hermie' is folklore Disputed. Properly produced feminized seeds from stable parents show no higher rate of intersex expression than regular seeds; poorly produced lines absolutely do Strong evidence[3].
When and where to look
Begin daily inspections from week 3 of flower onward, with higher frequency in weeks 5–8, when nanners most commonly appear.
Inspect at lights-on, before any disturbance or plant movement. Focus on:
- The main cola tips and the inside of dense bud sites.
- Areas closest to heat sources or light leaks.
- Plants already showing stress (yellowing, wilting, recovery from damage).
Use a 10× loupe. Nanners are small—often 3–8 mm long—and tuck between calyxes. A naked-eye scan will miss early ones. Look for a small, smooth, pointed or curved structure; it will differ noticeably from the hairlike pistils (white or reddish threads) that stick out from normal female flowers.
Step-by-step: removal protocol
1. Don't shake the plant. Pollen disperses on air currents and disturbance. Move deliberately.
2. Turn off fans. Kill oscillating fans and any active intake/exhaust for the next 5–10 minutes. Still air limits pollen drift.
3. Photograph and confirm. Use your loupe to verify it's a nanner and not a swollen calyx, stipule, or pistil tip. Count how many you see and on how many plants.
4. Bag before cutting. Bring a small zip-top bag to the nanner. Carefully slide it over the bud site, then snip or pluck the nanner inside the bag. This traps loose pollen. Never pluck in open air Strong evidence.
5. Seal and remove. Close the bag, take it out of the grow space, and dispose of it outside. Wipe your scissors with isopropyl alcohol.
6. Assess the plant. Count what you find:
- Single nanner on one bud near harvest: usually manageable—keep inspecting daily and remove any new ones promptly.
- Multiple nanners across multiple sites: the plant is committed to intersex expression and will keep producing them. Options:
- Isolate: move to a separate space if available.
- Harvest early: if within ~10 days of target harvest, pulling now often prevents room-wide seed set Weak / limited.
- Cull: in a multi-plant room with valuable genetics elsewhere, removing one plant can save the others.
7. Find and fix the cause. Check timers for drift, inspect for light leaks (all room lights off), verify canopy temps and humidity, inspect roots and soil. If you don't address the root cause, expect more nanners.
8. Post-harvest cleaning. After harvest, wipe down surfaces with damp cloths before the next crop. Pollen remains viable for weeks to months in dry conditions Strong evidence[1].
Common mistakes
- Spraying nanners with water to 'kill' pollen. Water can rupture already-dehiscent (open) anthers and spread pollen further. If you must spray, do it very gently and only after bagging the nanner.
- Using colloidal silver or STS (silver thiosulfate) mid-flower. These are reversal agents used early in flower to induce male flowers for controlled seed production Strong evidence[3][4]. Applying them after weeks of female flowering does not convert nanners or fix intersex expression; it will only contaminate your buds with silver residue.
- Ignoring a 'just one' nanner. A single nanner can pollinate dozens of nearby flowers. Seeded buds are not unsafe, but they are lower quality and lower yield in smokable flower.
- Plucking in open air. This is the single most common way to accidentally seed an entire room. Always bag first.
- Blaming genetics before environment. Most nanner events in home grows trace to a light leak, timer drift, heat spike, or severe defoliation—not the seed bank. Isolate variables before culling the plant.
- Running a known hermie line indefinitely. If a cultivar throws nanners consistently across multiple independent grows under clean conditions, the genetics are unstable. Replace your stock.
Related topics
- Pollen Collection and Storage — the same biology works in your favor if you want pollen.
- Sex Identification in Pre-Flower — how to spot true males and early intersex signals.
- VPD (Vapor Pressure Deficit) Basics — managing humidity and temperature to reduce stress.
- Schwazzing — aggressive defoliation late in flower can trigger intersex; timing matters.
- Inline Fan Sizing — proper airflow design to prevent hot spots and stagnant zones.
Sources
- Peer-reviewed Punja, Z. K., & Holmes, J. E. (2020). Hermaphroditism in marijuana (Cannabis sativa L.) inflorescences – impact on floral morphology, seed formation, progeny sex ratios, and genetic variation. Frontiers in Plant Science, 11, 718.
- Peer-reviewed Small, E. (2015). Evolution and classification of Cannabis sativa (marijuana, hemp) in relation to human utilization. The Botanical Review, 81(3), 189–294.
- Peer-reviewed Lubell, J. D., & Brand, M. H. (2018). Foliar sprays of silver thiosulfate produce male flowers on female hemp plants. HortTechnology, 28(6), 743–747.
- Peer-reviewed Ram, H. Y. M., & Sett, R. (1982). Induction of fertile male flowers in genetically female Cannabis sativa plants by silver nitrate and silver thiosulphate anionic complex. Theoretical and Applied Genetics, 62(4), 369–375.
How this page was made
Generation history
Drafted with AI assistance and checked by a separate automated fact-check pass. Not every article has been read by a person. See how articles are made.
Related
- Inline Fan Sizing — Choosing the right exhaust fan capacity for heat, humidity and odor control.
- Pollen Collection and Storage — Harvest and preserve male pollen to breed across flowering windows.
- Schwazzing — Aggressive early-flower defoliation technique with disputed yield claims and significant r...
- Sex Identification in Pre-Flower — Identify cannabis plant sex weeks before flowering to eliminate males and save resources.
- VPD (Vapor Pressure Deficit) Basics — How to use vapor pressure deficit to manage plant transpiration and prevent humidity-relat...