Only female cannabis plants produce the buds you want. Males make pollen — and pollen turns your flowers into seed bags. If you grow from regular (non-feminized) seed, or if a plant gets stressed, sexing and hermie-watching is the difference between a jarred harvest and a seeded loss.
Female vs. male — reading the pre-flowers
Both sexes show their identity at the nodes (where branches meet the stem), usually 1–2 weeks after the flip to 12/12 — or a bit earlier as "pre-flowers" late in veg.
- Female: a small teardrop-shaped calyx with one or two fine white hairs (pistils) poking out. Wispy, white, hair-like = female. This is what you want.
- Male: small round balls (pollen sacs) on little stalks, often in grape-like clusters. Round, smooth, no hairs = male.
Check every plant at the nodes from about day 7 after the flip, with a loupe if needed. Photograph and compare if unsure — the difference is obvious once you've seen it.
Why you must catch males immediately
One open male pollen sac can seed an entire tent. Pollen is fine, invisible, and travels on air and hands. If you're not deliberately breeding:
- Remove males the day you identify them. Do it gently (don't shake pollen loose) and get them out of the room.
- Regular seeds run ~50% male, so plan on culling half. This is why beginners buy feminized seed — ~99% female, no males to catch.
Hermaphrodites — when a female grows male parts
A hermie is a female that, under stress, also produces pollen — sacs or little yellow "bananas" (stamens) poking out of the buds. She pollinates herself and her neighbors, and you get seeds throughout your harvest.
What causes it (almost always stress):
- Light leaks / interrupted dark period — the #1 cause. A glowing LED or a peek with the room light on during lights-off can trigger it.
- Light schedule instability — a timer glitch, or repeatedly changing the cycle.
- Heat stress, severe over/underwatering, or nutrient extremes
- Harvesting way past ripeness (very late plants may throw a few "nanners" naturally)
- Unstable genetics — some cheap/hermie-prone lines do it under any excuse
Prevention
- Kill light leaks. Sit in the closed tent during lights-off; if you can see anything after five minutes, tape it. Photoperiod flower needs pitch-black, uninterrupted dark.
- Rock-solid timer. Verify it flips correctly; never manually disturb the dark period.
- Keep the environment steady — no heat spikes, no drought-then-flood.
- Buy stable genetics from reputable breeders.
- Don't harvest weeks late.
If you find nanners late in flower
A few stray bananas in the last week or two is common and usually low-risk — pluck them with tweezers and carry on; late pollen has little time to make viable seeds. A plant throwing sacs everywhere in mid-flower is a bigger problem: isolate it, decide whether to pull it to protect the others, and hunt down the stressor (almost always a light leak).
The one-line takeaway
Females = white hairs, males = round balls, hermies = stress. Grow feminized seed, seal your dark period, keep conditions steady — and your buds stay seedless.