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Hermies and Nanners: Why Plants Turn and What to Do About Seeds
By the Cultivar grow team · published 2026-08-04 · updated 2026-08-04 · how we source these numbers
Finding bananas in your buds at week six is one of the more demoralising moments in growing. The plant has decided its situation is bad enough that producing seed matters more than producing flower — or it was always going to, and nothing you did caused it.
Distinguishing those two cases matters, because one is a lesson and the other is just a plant to stop running.
What you are looking at
Two different presentations:
Nanners. Smooth, yellow, banana-shaped anthers pushing directly out of the flower, without a sac. These release pollen quickly and often without any obvious warning. Most common form, and the harder one to catch early.
Pollen sacs. Distinct grape-like or ball-shaped structures forming among the buds, more like what a male plant produces. Slower to open, so they give you more time.
Either way, once pollen is released, nearby flowers get seeded.
Check the interior of dense buds with magnification. Nanners often start deep inside where nothing is visible from outside, exactly like bud rot — and late flower is when both are worth looking for.
Stress or genetics?
Stress-induced — the plant was fine and then turned. Common triggers:
- Light leaks during the dark period. The most preventable and most common cause. A plant needs genuine darkness; a status LED, a gap in a zip, or light through a vent is enough for some cultivars.
- Interrupted light schedule — a timer failure, a run of inconsistent dark periods.
- Severe heat, particularly sustained. See heat stress.
- Serious nutrient problems or a badly damaged root zone.
- Physical damage, including aggressive late training or breakage.
- Harvesting very late, well past ripeness, where nanners can appear as a natural end-of-life response.
Genetic — the plant turns despite good conditions, or several plants of the same cultivar turn while others in the identical space stay clean. Some lines simply carry it, and some poorly-made feminised seed carries it more.
The diagnostic question: did anything change in the dark period? If you cannot rule out a light leak, assume it was the light leak — it is by far the most frequent cause and the easiest to fix.
What to do right now
If it is a few isolated nanners, caught early:
- Remove them carefully by hand. Do not squeeze or flick — you will release pollen.
- Wet them lightly first if you can; damp pollen travels less.
- Check the whole plant thoroughly with magnification.
- Inspect daily from now on. A plant that produced one nanner will usually produce more.
If it is widespread, or sacs have opened:
- Isolate or remove the plant. Pollen spreads through a tent readily, and once it is loose the whole room is at risk.
- Decide honestly whether it is worth keeping. A heavily hermied plant close to harvest may be worth finishing alone; one at week three usually is not.
- Assume some pollen escaped and watch the neighbours.
Either way: hunt for the cause. Check the tent for light leaks with the room dark and your eyes adjusted. Check the timer. Check min/max temperature logs for a spike you were not present for.
Is the crop still worth finishing?
Usually yes, with reduced expectations.
- Seeded bud is smokable. Yield of usable flower drops, and the plant diverts energy into seed rather than resin.
- Timing matters most. Pollination late in flower produces few mature seeds and modest impact. Pollination early produces a heavily seeded, disappointing harvest.
- Seeds take weeks to mature, so an early harvest after late pollination limits the damage.
Do not save the seeds
Tempting, and almost always a mistake. Seeds from a hermaphrodite plant:
- Inherit the tendency to turn, so you reproduce the problem in the next run.
- Have no separate male parent, so they bring no new genetic diversity.
- Are all female, which is the one attractive property — and not enough to outweigh the rest.
The exception is deliberate breeding, where a grower intentionally uses a reversed plant with known genetics for a specific purpose. That is a different activity from keeping whatever fell out of a stressed plant.
Prevention
- Eliminate dark-period light leaks. Sit in the tent with lights off for several minutes, let your eyes adjust, and look for anything glowing. Tape it.
- Use a reliable timer and check it periodically.
- Keep temperature stable and within range.
- Avoid heavy training late in flower.
- Harvest at ripeness rather than pushing weeks past it — see harvest timing.
- Note which cultivars turn. If a plant hermies in a clean environment, that information is worth more than any amount of effort spent rescuing it. Do not run it again.
- Light leak detector or blackout tape — dark-period light leaks are the single most preventable cause
- Jeweller's loupe or pocket microscope — spotting early nanners deep in a bud before they open
- Thermometer + hygrometer with min/max memory — heat spikes you never witnessed are a common trigger
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FAQ
What is a hermie in cannabis?
A plant showing both female flowers and male pollen-producing parts. It appears either as distinct pollen sacs among the buds, or as "nanners" — smooth yellow banana-shaped anthers pushing straight out of the flower — which release pollen and seed the crop.
What causes a plant to turn hermie?
Two broad routes. Environmental stress in flower — light leaks during the dark period, extreme heat, severe nutrient problems, physical damage, or a badly disrupted light schedule. Or genetics, where a particular plant carries the tendency regardless of how well it is grown.
Should I remove a hermie plant?
If it is producing pollen and you care about the rest of the room, yes — or isolate it immediately. Pollen spreads easily and seeds the entire space. A few isolated nanners caught early can be removed by hand, but check daily afterwards.
Are seeds from a hermie plant worth keeping?
Generally no. They inherit the tendency to turn, so growing them tends to reproduce the problem. There is also no male parent, so they carry no new genetic diversity.
Is seeded bud still usable?
Yes, though yield of usable flower drops and quality is usually lower, since the plant diverts energy into seed production. Caught late in flower the impact may be modest; caught early it can be substantial.
Keep reading
- Light Burn and Bleaching: Too Close, Too Bright, or Too Hot?
- Heat Stress in Cannabis: Taco Leaves, Foxtails and What to Fix First
- Brown or Rust Spots on Cannabis Leaves: Calcium, pH or Pests?
- Bud Rot (Botrytis): Catching It Before It Takes the Harvest
- Drooping Cannabis Leaves: Overwatered or Underwatered?
- Fungus Gnats: Small Flies in Your Grow and the Larvae That Matter
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