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Can pulling dep tarps off at night cause hermies?

blackg0d

Member
Our dep houses just started showing nanners unfortunately. Were at week 4/5 of flower. We have been pretty damn on top of depping on time, although we have been doing it manually. We've never depped more than 5 minutes off of 11:45/12:15 consistently, and 95% of the time it's within less than a minute. We have had tiny light leaks in the tarp, but nothing that actually makes the plant visible or light up. We get lots of holes from our shitty dep situation, and patch them as soon as we see them. We check underneath the tarp every time to make sure its dark in there and it is absolutely DARK.

Where we are, sunrise is around 6am. We dep at 5:45pm and then take the tarps back off once it's completely dark outside, to let the greenhouses ventilate and experience natural darkness and sunrise. We have intake, exhaust, and oscillating fans to ventilate the houses for the 4 hours they are covered. One of my friends claims that he always has problems doing it this way, because he thinks the shift from complete darkness to moonlight is too severe. Which makes sense to me considering on bright nights there's a big difference in darkness under the tarp and darkness in full moonlight. Can anyone speak on this?
 

Deezl

Member
I just started depping today and the greenie has no light traps or outtake fans for now (soon come).
I put the tarp on at 8pm off at 10pm and I'm going to put it back on from 5am till 8am.
I've always heard that is fine, I guess I'll find out!
 

CanniDo Cowboy

Member
Veteran
Our dep houses just started showing nanners unfortunately. Were at week 4/5 of flower. We have been pretty damn on top of depping on time, although we have been doing it manually. We've never depped more than 5 minutes off of 11:45/12:15 consistently, and 95% of the time it's within less than a minute. We have had tiny light leaks in the tarp, but nothing that actually makes the plant visible or light up. We get lots of holes from our shitty dep situation, and patch them as soon as we see them. We check underneath the tarp every time to make sure its dark in there and it is absolutely DARK.

Where we are, sunrise is around 6am. We dep at 5:45pm and then take the tarps back off once it's completely dark outside, to let the greenhouses ventilate and experience natural darkness and sunrise. We have intake, exhaust, and oscillating fans to ventilate the houses for the 4 hours they are covered. One of my friends claims that he always has problems doing it this way, because he thinks the shift from complete darkness to moonlight is too severe. Which makes sense to me considering on bright nights there's a big difference in darkness under the tarp and darkness in full moonlight. Can anyone speak on this?

Bummer dude. No, light deppen does not cause hermies and your tarp on-5:45pm/tarp off after dark schedule is right on the money. Doing the dep manually has nothing to with anything causing hermies either. Hermies have been known to happen if the plant is repeatedly stressed i.e.-frequent under watering, drastic temp changes etc. Ive also suspected high ppm counts caused by some of the more potent chemical nutrients available. Just a suspicion tho. Sometimes the problem is as simple as a missed male- from seed or clone. Check the plant to determine if in fact both male and female characteristics exist at the same time.

A few other and more common hermie causes IMO are inferior seeds caused by poor breeding techniques and feminized seeds which have always been notorious for throwing nanners.

Actually, the notion that your greenhouse has to be absolutely dark is a myth. A few pin holes or even a small fabric tear here and there is a non-issue. If you reduce the amount of overall light by 75% on the proper schedule, the flowering phase will undoubtedly kick in...The only 2 possible but rare issues associated with light deppen is the initial flower mode triggering of the run and not doing anything adverse to cause the plants to revert to veg. Those and waking up in the a.m. to find your tarp is in the neighbors yard - been there, had to go fetch that...cc
 
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Speed of green

Active member
IMO there is no acceptable amount of light leakage, complete darkness is key.

some unstable genetics take very little amounts of stress to herm.

I would check your seed stock and get a better tarp. start ruling out variables.

good luck
 

Deezl

Member
I went out out to cover this morning 15 min before "civil twilight" (5:15am) and it seemed like it was already too light so I didn't cover. I guess my dep starts today instead.
 

troutman

Seed Whore
Is there street lights or other domestic lights nearby?

If so I would leave the tarps on at night.

Any light in the dark period could over time give you problems.
 

Chunkypigs

passing the gas
Veteran
Kevin at Wonderland Nursery mentioned in one of his talks that a small percentage of Cali genetics have been unstable and herm in light deps but are OK indoors or full season.

lots of potential stress in a dep and everyone has a different set up so it's apparently tough to generalize about what always works at this point.
 

CanniDo Cowboy

Member
Veteran
Long term flowering is normally triggered by a shortening of day lite hours as per fall vs summer, not how dark it gets as the flowering portion of the season begins. Hence, allowing a few pin points of light won't make a difference either way. Consecutive cloudy days can actually trigger flowering in some "trigger happy" strains. Light deppen by itself does not cause stress. Over 10,000 Emerald Triangle (Humboldt County) light deppers wouldn't be doin it if the technique causes hermies. Google it bro, I think the problem may lie your seeds.

The standard method is pull tarp at approx 5-6 pm and remove after full darkness so as to avoid over nite condensation build up, enclosed air environment issues etc. No need to leave the tarp on all nite. The critical time is when the tarp is first pulled. Depending on your own region, from 5pm til dark can cause inside temps to rise. Usually the plants will adjust to this 2 hour or so covered period and Ive never known it to cause any problems but- If, when removing the tarp after dark you are met with a blast of built up heat, stifling air or an overwhelming "tarp" smell or the plants look to be wilty/struggling, you may want to consider an air intake/exhaust/cooling application while tarp is in place.....Hey, ya know it don't come easy......cc
 
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Chunkypigs

passing the gas
Veteran
here's Kevin talking about deps and herms at 30 seconds in.

russet mite killing at end.

[YOUTUBEIF]GbywPWBoM3s[/YOUTUBEIF]
 

blackg0d

Member
Long term flowering is normally triggered by a shortening of day lite hours as per fall vs summer, not how dark it gets as the flowering portion of the season begins. Hence, allowing a few pin points of light won't make a difference either way. Consecutive cloudy days can actually trigger flowering in some "trigger happy" strains. Light deppen by itself does not cause stress. Over 10,000 Emerald Triangle (Humboldt County) light deppers wouldn't be doin it if the technique causes hermies. Google it bro, I think the problem may lie your seeds.

The standard method is pull tarp at approx 5-6 pm and remove after full darkness so as to avoid over nite condensation build up, enclosed air environment issues etc. No need to leave the tarp on all nite. The critical time is when the tarp is first pulled. Depending on your own region, from 5pm til dark can cause inside temps to rise. Usually the plants will adjust to this 2 hour or so covered period and Ive never known it to cause any problems but- If, when removing the tarp after dark you are met with a blast of built up heat, stifling air or an overwhelming "tarp" smell or the plants look to be wilty/struggling, you may want to consider an air intake/exhaust/cooling application while tarp is in place.....Hey, ya know it don't come easy......cc

I've googled it plenty, bro. What you are explaining is exactly what we have been doing. We have intake, exhaust, and oscillating fans running while the tarps are on. We pull them off in full darkness. I am leaning towards genetics as we did this run from clones of unknown age.. We have had them vegging since February. Thats the only uncontrolled variable and it sounds like we've done everything else right.
 

CanniDo Cowboy

Member
Veteran
I've googled it plenty, bro. What you are explaining is exactly what we have been doing. We have intake, exhaust, and oscillating fans running while the tarps are on. We pull them off in full darkness. I am leaning towards genetics as we did this run from clones of unknown age.. We have had them vegging since February. Thats the only uncontrolled variable and it sounds like we've done everything else right.

Yea, when doing light dep, it's important to know everything possible about the history and tendencies of the strains/clones you're running. Are your clones first cut from the mother or clones from clones from clones with the mother a long ways back? As Chunky said, there is a lot of dynamics to consider when it comes to a hermie problem...cc
 

Noonin NorCal

Active member
Veteran
Is there street lights or other domestic lights nearby?

If so I would leave the tarps on at night.

Any light in the dark period could over time give you problems.

I was gonna say the same thing, we have street lights. last year we started covering from 7pm-7am, i think its better that way
 

Deezl

Member
So, this morning I got the tarp on about 5 min before civil twilight (I've been doing it 15 min earlier on most days) and it seemed really bright out. The plants don't see that amount of light I guess? It was probly light enough to read.
 
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