How big of a light leak is too big? Will a pinhole cause hermies?

So I've got a question here, and I've already got a suspicion.

I've got a grow going in a closet that has been converted to two cabs.

One will be used for flowering, though both are currently running 24/0

My concern is light leaks.

The door to my cab is currently a piece of panda poly. However it isn't sealed. I'm going to use a new piece tomorrow, and use adhesive zippers to create a flap that unzips.

My concern is getting it all 100% sealed.

In doing this, I'm wanting to gather some information. Now I'm going to set the cycle similar to the actual daylight, so that as many of the 12 hours of dark are during actual dark times. I'm thinking 6PM to 6AM.

Now the only light that could get in is either residual sunlight coming into the room the closet is in, which would be during sunrise, which is before 6AM most times, or until sunset, which is later than 6PM.

OR any light from the CFL that lights the room the closet is in, though that is usually off by 10PM or so.

So basically I'm wondering how much light it'll take to cause a potential problem with hermies.

I'm not certain how tight I'll be able to seal the "door" made of panda poly. I'm also not sure how light tight the adhesive zippers will be.

This has been my main concern all along, and has always seemed to me to be an area of real difficulty.

The door has to be removable, but also light tight.

Now I'm guessing everyone is going to say that any light is too much.

Is this truly the case?

IE, the plan is to have one person seal the other inside the room, and the person inside the room can then see if there are any leaks whatsoever. Basically it should be 100% dark, correct? No ifs ands or buts, right?

Even if there is the slightest shadow of dim light coming through, is it too much?

Or are plants more tolerant than I think?

can u just close the closet doors 6pm-6am??
im guessing a pinhole is really bigger then that, plants dont tolerate light well...atleast not when its supposed to be there 12h......ive had some herm's over a pinhole size spot, yes.

Just some food for thought...
I know that we all strive for 100% dark, but that does not happen in nature.
How much light do outdoor plants see when there is a full moon? Is that causing hermies? And how would the diffusion of the suns light bouncing off the moon compare to a pinhole allowing the light from a small bulb at how many feet away? My money is on the moons reflection of the sun putting out more lumens.

I grew out 1 indica and 3 sativas outdoors last year, and there was a MH street lamp within about 200 ft. of where they grew. One of the sativas started to hermi right at flower, and the indica was already well on it's way to full buds, so I chopped when I saw the first couple pods. I have no idea if this was simply a full on hermie from the bag seed I used, or if the light triggered this...I didn't really care. The other plants finished fine with no hermie at all, even late into flower.

Digi, I am not convinced that you can for certain say that a pinhole of light hermied your plants. Too many other factors that can bring about a hermie to make that call.

I, Too, think some people make much ado about a little light. I am growing from bagseed, and have brought 8 plants to flower in my cabnet. I know I have some small leaks, I would say more than pin holes, but I got no hermies.

Do all you can do and give it a try.

Triv

the light coming off the moon is nothing compared to a pinhole, which focuses light in a concentrated area. try to fix as many leaks as you can because i had a small leak and got multiple hermies and a seeded crop. it is not fun smoking buds with little micro seeds in it that pop when you smoke it.

koopa - how long before harvest did ur plants start to herm that they produced micro seeds? i got a couple nanners poppin but since im only a week from chop i haven't been stressin too bad. def. thinking light leak tho, since only the plant closest to the crack of the door is throwing nanners...

from recent experience the zippers let a lot of light through, so some sort of flap over the vipper neds to be made. also panda plastic rips and gets holes in it pretty easy, i have a few of them in mine and im trying to find the best way to close the holes.. any kind of tape doesnt seem to work well for closing them up.

hbstoner said:

from recent experience the zippers let a lot of light through, so some sort of flap over the vipper neds to be made. also panda plastic rips and gets holes in it pretty easy, i have a few of them in mine and im trying to find the best way to close the holes.. any kind of tape doesnt seem to work well for closing them up.

Click to expand...

yeah I noticed that the panda is super easy to gouge/rip, at least to the point that it lets light through.

I was worried about that with the zippers.

I'm thinking I might go with 2 layers of panda. The first one will be the true door with tarp zip-ups etc, the other one will be just attatched at the ceiling of the cab, and hang over the door.

That way any leaks in the first door are covered by the 2nd.

This really seems like one of the toughest parts of the grow.

Mind you it's not like there is other HID light that could come through. I've sealed up any leaks (though yet to test) between the two cabs, as that was another concern, since in the veg cab I'm running two 105 watt CFLs.

I'm going to experiment with the doors today, as if I could close them, that would be nice.

But I also need to somehow create a light tight intake, I'm thinking about drilling holes in the cab ceiling which is plywood, and taping down a piece of ducting in a "U" shape.

Other than that, my other concern is the seal against the floor. My plan is to just tack the door into the walls with thumbtacks, but the door has to be removable, to access the plants.

I was planning on sealing it to the bottom of the floor with velcro, but that might also leak. That's where the 2nd piece of panda poly comes in I guess.

So many places that this could go wrong.

Hell, it could even leak if I didn't have it completely flush with the wall.

And oh, did I mention I still have to account for the wiring coming out of the room?

Two thick power cords going to my reflectors.

I guess I could just run that against the wall, and push the poly tight against it.

This is one thing I guess I seriously underestimated.

It is not an easy task to light proof a room. Not by any means.

I guess we could do it another way.

Make it a house rule that during 6PM and 6AM, the blinds stay shut, and nobody is to turn a light on in the bedroom.

Only reading by a little LED light.

Dunno how my wife would like that one though...

She might not really mind, who knows.

Either way, we're in for a helluva task today getting this baby all proofed up.

The panda I have is 5.5 mil thick, and I've yet to even see what I've got for leaks.

Though I'm also still on 24/0, for obvious reasons.

This is the big thing holding me back from the 12/12 switch.

So to sum up, my main areas of concern:

Creating a "face wall" that is light tight, but also contains a "door flap" that can be removed/folded up for easy access to the plants.

Sealing the "face wall" against the other walls/hard surfaces, side walls (using tacks?), floor (velcro?), etc. Yet light tight.

Making sure the zippers are light tight (a 2nd flap of panda poly?)

Creating an intake that is light tight.

Making sure the wires coming out of the cab are not creating light leaks.