How small a light leak causes hermies?

[FarmerGreen]

I was just wondering how big a light leak actually has to be to cause hermies.

I'm only thinking about it cos when you grow plants outside they must see all sorts of light at nighttime- moon, streetlights etc, and you don't get a hell of a lot of hermies then

 

[Hawk]

I've wondered about this too.

 

[SvenB]

Good question, Id like to know too

 

[Miko]

Every plant is different.

 

[Wonderon]

Just my thought on it.

Direct light is not the same as moonlight, all the moon will do is cause some stretch but by all means a street light might mess up your garden. As far as I know with an inside garden even a small opening of crack in the door can cause stress on the plant and in turn cause it to hermie.

 

[jawnroot]

Plants have evolved with diffuse 4100K light present at night (ie: moonlight). Moonlight is very low energy, and by its very nature is reflected light.

A street lamp, by contrast, is relatively high energy, and is a direct source of light.

The point of all this is that a plant can take moonlight, and that's about it. Most other sources of light are direct, or point sources, and will be higher energy, and thus have the potential to do damage.

In other words, if you're growing outdoors, make sure it's pretty deep in the forest, so as to avoid all the various artificial sources of light. If you're growing indoors, make sure your box is sealed 100%.

 

[hoosierdaddy]

A non hermie plant isn't going to hermie, unless it sees a tremendous amount of stress'.

I grew three large bushes last year that were within 200 ft of a MH street lamp.
No problems. I did have a fourth plant that hermied immediately after budding, but I cannot say it wasn't a hermie prone plant to begin with.

The others showed no signs of hermie all the way through a full harvest period.

 

[smokeymacpot]

my cab has never been sealed 100%, gaps round the doors, fan holes uncovered e.t.c and no hermi's...
but if direct sunlight shines on your cab and gets through the gaps it may well affect it in that it might go into reveg (or may hermi, but its unlikely). your main room light will not affect your plants, even if you have the cab open, its too far away and too weak and if that was the only light it ever saw, your plant would never go green and it would die, just as it would if it had complete darkness.

most of the time cannabis will hermi by itself, best way to avoid that is to take clones from a stable mother, eg flower a plant and then reveg it, if you see no male flowers throughout all that then all your clones should be safe.

 

[jawnroot]

I suppose it boils down to this: you can take a chance with light leaks, and risk a whole crop/season on it, or you can be prepared.

 

[Miko]

Direct or inderect light it don't matter. What matters is most probably light intensity and spectrum.

 

[hoosierdaddy]

BINGO, Miko!

The effectiveness of an HID is reduced exponentially with just the move of a few inches.
Even to a point that decent buds cannot be grown if the light is say 12 inches further than optimum. Take the same light 10 ft away and grow zero buds...or little airy things that aren't worth the trouble.
Now, if a street lamp with a 250w MH is 200 ft away, just how much intensity is that light providing? Enough to make the plant think it is seeing a change in photo period? Not if it is a true breeding non hermie plant. It won't even know it's there...or care.

Moonlight is very low energy, and by its very nature is reflected light.

Hmmm...let's look at the period just after sunset. Still lots of light around to see with, and do we think a plant will just neglect this light because it is being reflected instead of direct? The light from the sun is HIGH ENERGY, and even if an outdoor plant never sees the sun directly, it can still produce a good harvest simply by surviving on the diffused reflected light that the sun puts out.

The thing about the moon, is that there are things we don't understand about it. IMO, it is used in nature as a signal devise to plants, and the reflected light it produces is probably connected with that whole thing. It's gravitational force alone is one of the most powerful things man is aware of.

 

[One Love]

It doesn't take much light to cause hermi's, at least thats been my experience indoors. I think one key thing is how long (how many consecutive days) the plants are exposed to the light leak. I have just recently dealt with this problem; I had my clones rooting in the corner of the room under a small cfl (the big girls are in the closet). After a few weeks i noticed some male parts showing up on my NL x BB and Sk#1. So i sat in the closet right at lights off and nearly shat myself when i saw the cfl light from the clones seeping under the panda film, weather stripping and door crack into the closet.

I would say (generally) you're ok if you have a little light leak for say a day or two, but it often goes unchecked until some sort of stress shows up. i.e. i thought i had taken all necessary precautions with adding the panda film and weather stripping, but I found out differently when the male parts showed up.

As some others have said its important, when working indoors, to completely take care of all light leaks. 100% light proof and then you don't have to worry much about it.

Another thing i've read about hermi's is that a plant is said to have these tendencies within its genes and that a "true" female will never hermie, even with some light stress. i.e. my White Widow clone has no male parts and experienced the same light stress as the other girls. I am not sure either way, but it really is a shitty problem to have. Everything looks so beautiful as you're looking your girls over then all of the sudden doh!!

anyone have a better way to light proof a closet besides panda film and weather stripping?!

 

[smokeymacpot]

one love:
you cannot really say for sure that the cfl light leak caused a plant to hermi. were they grown from seed? im pretty sure they would have hermed on you anyways. try the same again but use clones from a stable reveged plant.
cfl is not effective when the bulb is say 50cm away and they just dont see it, or get any useable light from it.
this comes from experience and growing a very hermi prone strain, well thats what people on the internet have said, blah blah, loads of hermis from superskunk e.t.c you just get the odd one or two every now and again grown from seed that will hermi no matter what you do, those plants get thrown away.
ive done other strains where alot come out hermi,, but i start quite a few and flower then reveg and the ones that show no male parts are stable and will never hermi, no matter what u do.

 

[Haps]

When I see hermi's, it is always beside plants in the same conditions that do not hermi. From this, I believe it is the genetics and not the light or other stress conditions.
H

 

[One Love]

Smokey, thanks for the insight. That would explain why my WW clone did not show any male parts. Sadly I wish this wasn't the case, as this was my last Sensi SK#1 bean and I thought I had lucked out when i found it was a fem. I will try the SK#1 again (from clone this time) on my next run and if those show male parts then I will trash it and go back to ordering some different genetics. How disappointing this is, my two best plants did the same thing.

This has me wondering about the breeding process. I just didn't think that Sensi Seed co. would have something (especially sam's SK#1) with hermi prone genetics, but I have no evidence to back up that thought.

Hope everyone is doing well and staying hermi free!

 

[Stone]

It is true that some plants are genetically hermaphrodite, and will show that trait even under stress free conditions.

However, I believe some hermies who would show themselves under a light leak (or some other stressor), are able to supress this condition in a stree free environment.

So having your light leaks sealed just may stop a hermie from showing 'itself'.

If you're looking for true females to be used for breeding, many accomplished breeders stress a plant in this way.
That will tell you your plant is a 'true' female.
In fact, this is sometimes better as it stops genetics that are easily hermied from propogating.

 

[FarmerGreen]

Sweet. What a lot of good info. I was wondering whether I should be triple light proofing the join between my cloning chamber and the flowering chamber. Seeings as I can't really be assed, I might just leave it and see what happens. It's probably pretty sealed anyway.
Thanks again!

 

[GET MO]

my folks had a security light that would come on at all different times of night(from rabbits and stuff, or if he was in the crop at night) for the last couple years.... never had hermie problems. guess it just depends...

 

[bobblehead]

yeah, what's been said already. It's plant dependent. The ones that hermie in my experience will do it from a pinhole light leak. Then there's some that never throw a nanner no matter how much you mess with the light cycle.

 

[Scottyboycx]

i found a hermy otherday .... a bagseed thats been in flower for 10week...i feel so stupid but after check everything out about 3 times i finally found my light leak......the red light on one of my timers lol DoH!