Herms in lower/ shaded larf VS. Herms in top colas

What is the difference I(genetic, stress, etc...) between herms at differant points in the plant canopy?

So i'm growing quite a few strains. Two in particular, Sinderella and ChemDog, have herms. Now, the Sinderella herms were all on lower shaded larf and bullshit that I should have pruned off initially; no big deal, i can just cut those off. On the ChemDogs however, I started seeing herms (just green stamens, not full flowers) in the colas. Full light, healthy plants, no visible stress (maybe heat? temps peak at 85ish in the mornings), etc. Plants are at Day 26, 1000W HPS, pH/EC in is about 5.8-6.0/1.8-1.9.

Any plant scientists that can explain herms, their causes, sensitivities, etc.. to me? I'm curious if it's something I can prevent in the future, or if its an inevitable genetic trait these cuts will always express.

Id say difference in vpd and PAR might play a big role in transpiration gradients up a down the plant creating enough stress at different places around a canopy depending on your grow style.. like very densly packed canopies in scrog grows being more easily low RH above canopy and high below and inside.

The way light is directed by grow lights creates uneven shade spots, so basically the plant goes from light to shaded in certain spots and throws herms there. Similar to thinking about it as kind of like "light leaks" on certain parts of the plant. An example of how the plant reacts to changes in light on different areas is shown by the idea that you can darken a branch 12 hours a day and it will flower on that branch. Same idea. Use low wattage bottom lighting or lollipop.

707OGBUSH970 said:

Use low wattage bottom lighting or lollipop.

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This is pretty interesting. Is this a common thing people do? Any lights?

Yeah, I use the led bar lights and place them strategically under the plants. Im not sure how common it is, but Ive definitely seen other people do it on the forums and in person. You don't need much. Maybe like 5-20 watts per sq ft. 20 would be overkill imho. YMMV. Cheers!

By the way, If you are working with hermie-prone strains, get some Florel. It can and will make a plant going full on herm revert back to female. Use as directed.

707OGBUSH970 said:

By the way, If you are working with hermie-prone strains, get some Florel. It can and will make a plant going full on herm revert back to female. Use as directed.

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This also interests me. Do you just follow directions on the bottle? Unfortunately, abiding by the rules an regs of medical in my state, I can't spray my plants once in flower.

Yeah, the stuff works but I would not use it unless absolutely necessary, especially not if you are a med grower for other patients. The choice between a completely seeded crop and a little residual Etephon, I would definitely spray the Florel if for my own use. It works as that Etephon breaks down into ethylene, but Im pretty sure there are other banned agents in the stuff as well. I feel like if you use it that the right time, you dont need to reapply and Ive used it about half strength (100 ppm) with good results. Ive used it 5 times in my life over 20 years of growing. Something to consider. Are you having real herm issues or just curious? IMHO its genetics first, environment second. Some thai influenced stuff herms if you look at it wrong, it seems.

When I ran into the problem of herms at the bottom of one plant and the top of another in the same grow it was because the light leak was hitting the one with bottom herms mainly on the bottom and the poorly timed light was hitting the top of the plant with top herms.

Technically, true hermaphroditism (hermie, herm, etc.) is when the full male flower appears on a genetically female plant during the plant's normal growth cycle, and coinciding with the normal expression periods for male flowers. This is what you're experiencing on the lower growth at the axillary junctions and around the base of lower buds. These flowers generally have five anthers arranged in a cluster hanging from filaments coming from inside the male calyx, and in my experience their presence on female plants is more related to the genetic degeneration of sex linked traits in drug strain cultivars than on environmental stressors.
"Nanners" on the other hand are what you're seeing up in the colas, and those are clusters of anthers that appear much later in the growth cycle, often long after genetic males would have passed dehiscence and died. They can appear in any number, and will take the place of female calyxes in the upper canopy. These appear to be more due to environmental stress, and can certainly be caused by temp/humidity spikes, or light leaks, but these are hormonal changes that take place throughout the plant, so there are many ways to catalyze that.

It's also important to remember that growing seedless drug strain cannabis is naturally a stressful process for the plants, and that countless other plants have evolutionary strategies around the challenge of sex-homogeneity in isolated populations, so the fact that cannabis can also thwart our efforts to keep those girls chaste shouldn't be all that surprising. It just makes the pheno hunt that much more exciting.