worries for light deprivation - Growing in Greenhouses - International Cannagraphic Magazine Forums

The Bling · 12-25-2008, 06:02 AM

next spring i want to have a light dep tunnel so that after it gets dark each night i can cover the lovely ladies up and take the covers off like 11-12 hours before sunset Im worried about heat light leaks causing hermies and humidity do i need airmovers under the covering what type of covering should i use is heavy duty tarp enough to block the morning sun or would sometipe of blackout be better thankyou all so much blessings from the most high happy holidays

12-27-2008, 12:30 AM

punctuation is your friend man, that was a struggle to read and I am still not sure I understand exactly what you are trying to do.

Jah (b)less · 02-15-2009, 04:36 AM

You can get blackout plastic from greenhouse suppliers that is used just for this purpose, its black on one side white on the other. You should cover your plants at 12 hours then remove the cover after darkness that way there is no humidity build up

jtk707 · 02-18-2009, 12:44 AM

but not a blue one , even some brown ones let sun in . Black one are hard to find . I found the best ceapest covers for greenhouses at a diesel truck used parts place . peace

f punctuallity

02-18-2009, 03:00 PM

hi The Bling,i have some experience with shading plants, for those light leaks problems i think that Jah (b)less gave you right advice, and humidity well..... there will be high humidity for sure, you can solve it with choice of certain strain, haze hybs can take alot of humidity without mold problems, but theyre also longer flowering plants, and if it will be spring grow i guess you need some fast flo strains, so then you should have good airflow whent it is covered and add some good dehumidifier, just turn that dehumi on for a little while, it doesnt need be turned on for long time, it also kills organisms in air which can attack your plant

but i think the best is learning from your own mistakes.....

peace an good luck with your grow

buzzerd · 02-18-2009, 04:09 PM

i don't understand why you would want to deprive your plants of light unless you are looking to either pull out the indica or sativa side of a specific plant or some other trait that you are looking for. DJ short has done work along these lines and this is how he isolated some of his berry strains.
I do know that at the first sign of sex of an outdoor plant determine the length of daylight for that day,then count back 10 days and determine the daylight for THAT DAY. That will then tell you how many hrs of darkness that plant will need for blooming.
Any way depending on what you are doing and how much time that your going to have to do this you better be very dedicated to follow through with your plan just 1 screw up could possibly get your whole patch.And for maybe 2-3 hrs of work a night every night IMHP not worth the time of having that last beer with the crew after work or dinner date with the old lady hell forget going out of town too..LOL
And in case you don't want to go through all the hassel of figuring out all the light cycles look here they have done it for us FOR THE WHOLE WORLD any city any country god bless them :
https://www.gaisma.com/en

Good luck with your project keep it green......Buzzerd

jtk707 · 02-19-2009, 04:41 AM

you can harvest two to four times in a green house using light deprivation techniques

nomaad · 06-19-2009, 06:25 AM

I just started pulling tarps over my two 15x16' hoophouses tonight at 8pm. We'll pull the tarps off at 8am every day.

I did a lot of research and bought 2 DuraTarp Silver Super Sun Blockers from creativeshelters.com... one 40x50 and one 40x40 (i originally was going to do one 50x16' hoophouse with a lot more plants, but the sheriff came by and made me take some down)... anyhow, by no means do these tarps block out all the light. I went inside and let my eyes adjust and i could just barely see light comeing thru the tarp. Amd its 8pm... the sun is behind treees at this point in the day, so we're not even talking about direct sun.

I am hopefully going to be able to get away with adding a layer of 6mil black plastic and not have to go out and buy a ton of expensive "panda" plastic... the kind you use to line the walls of an indoor grow room.

SweetHempSeeds · 06-19-2009, 05:43 PM

Hi there, I run lite dep, ive got a crop at 54 days now.

What ive found works best after a few years:

I use a poly silver/black hay tarp from farmtek. Silver side up to reflect lite. There is a bit of lite (pinholes) in the tarps, but they work just fine. Ive not had any hermie issues in 4 years of using this tarp.

On humidity, there are ways around it. One is to put the tarp on at dark, take it off when it totally dark, then put it back on before sunrise. If you have alot of air moving (fans) you can just open the ends, its much easier to close the ends at 4 am than pull the whole tarp.

I live in an extremely dry area with low humidity, so I just leave the tarp on til its time to remove it. When I pull it off my humidity is in the 90's, but within 45 minutes it is back into the 30's. IMO this is considered 'humidity shock' and wont allow any type of fungi to establish itself. I think it you tried this in a humid area it would not work (leaving the tarp on and letting the humidity get so high).

I also use only shdeclothe on my greenhouse frames in summer. This allows exponentially more airflow. I roll up the covers and leave them attached to the frames, and can pull them on when foul/cold weather comes in fall, to keep my buds dry.

Good luck!

SHS

nomaad · 06-21-2009, 05:52 AM

I considered the farmtek tarp, but it was twice the price of the Duratarp, so I went the other way. We started working with a 6mil black visqueen under the Duratarp. We pull the black plastic first in one direction, then the tarp over in the other. It is now completely dark in there- after about 5 minutes of eye adjustment there is zero visible light. d-a-r-k

SHS: I don't have the experience to disagree, but the sum-total of the wisdom I have collected from large commercial black boxes does disagree that absolute blackness matters. Strains that are prone to hermaphrodism will herm (so no awesome landrace sativas) and later blooming are the reasons cited for the absolute darkness regime. I have been specifically warned against opening up for the late night.

While I have not grown extennsively in N.America, I have grown in Central America. There, we use supplemental light to grow hybrids and indicas. We have found that, without a doubt, if we start to play with light cycles the process benefits significantly by imposing complete darkness during the dark part of the cycle.

I still appreciate and respect your experience-based wisdom. It makes me think "I'm glad its totally dark in there, but I guess I don't have to be so paranoid that a pinhole leak is going to ruin everything." so thanks.

Sooooo... 57 days in? I'm jealous. That's basically when I got back from Central America... I had this fantasy that my black box would be up a week after getting here, but it took just a wee bit longer- had to find a place and build 500ft of fencing!

So, what strains? Hows it going? How much longer till it comes down?

12-25-2008, 06:02 AM	#1
The Bling Is right 60% of the time everytime. Join Date: Nov 2006 Location: Mars Posts: 497	worries for light deprivation next spring i want to have a light dep tunnel so that after it gets dark each night i can cover the lovely ladies up and take the covers off like 11-12 hours before sunset Im worried about heat light leaks causing hermies and humidity do i need airmovers under the covering what type of covering should i use is heavy duty tarp enough to block the morning sun or would sometipe of blackout be better thankyou all so much blessings from the most high happy holidays __________________ I have a fridge full of weed, and a safe full of food.
	Quote

12-27-2008, 12:30 AM	#2
mexilandrace Guest Posts: n/a	punctuation is your friend man, that was a struggle to read and I am still not sure I understand exactly what you are trying to do.
	Quote

02-15-2009, 04:36 AM	#3
Jah (b)less Need money for weed Join Date: Jan 2009 Location: out there in the distance Posts: 115	You can get blackout plastic from greenhouse suppliers that is used just for this purpose, its black on one side white on the other. You should cover your plants at 12 hours then remove the cover after darkness that way there is no humidity build up
	Quote

02-18-2009, 12:44 AM	#4
jtk707 Califonia Love Join Date: Jun 2008 Location: Norcal Posts: 506	Use tarps but not a blue one , even some brown ones let sun in . Black one are hard to find . I found the best ceapest covers for greenhouses at a diesel truck used parts place . peace f punctuallity __________________ If you want it to rain .... Hang some buds up to dry If you want it to be windy .... Try to setup a greenhouse
	Quote

02-18-2009, 03:00 PM	#5
1000ARMSofKALI Guest Posts: n/a	hi The Bling,i have some experience with shading plants, for those light leaks problems i think that Jah (b)less gave you right advice, and humidity well..... there will be high humidity for sure, you can solve it with choice of certain strain, haze hybs can take alot of humidity without mold problems, but theyre also longer flowering plants, and if it will be spring grow i guess you need some fast flo strains, so then you should have good airflow whent it is covered and add some good dehumidifier, just turn that dehumi on for a little while, it doesnt need be turned on for long time, it also kills organisms in air which can attack your plant but i think the best is learning from your own mistakes..... peace an good luck with your grow
	Quote 1 members found this post helpful.

02-18-2009, 04:09 PM	#6
buzzerd Member Join Date: Jul 2004 Location: cali Posts: 233	good luck i don't understand why you would want to deprive your plants of light unless you are looking to either pull out the indica or sativa side of a specific plant or some other trait that you are looking for. DJ short has done work along these lines and this is how he isolated some of his berry strains. I do know that at the first sign of sex of an outdoor plant determine the length of daylight for that day,then count back 10 days and determine the daylight for THAT DAY. That will then tell you how many hrs of darkness that plant will need for blooming. Any way depending on what you are doing and how much time that your going to have to do this you better be very dedicated to follow through with your plan just 1 screw up could possibly get your whole patch.And for maybe 2-3 hrs of work a night every night IMHP not worth the time of having that last beer with the crew after work or dinner date with the old lady hell forget going out of town too..LOL And in case you don't want to go through all the hassel of figuring out all the light cycles look here they have done it for us FOR THE WHOLE WORLD any city any country god bless them : https://www.gaisma.com/en Good luck with your project keep it green......Buzzerd
	Quote

02-19-2009, 04:41 AM	#7
jtk707 Califonia Love Join Date: Jun 2008 Location: Norcal Posts: 506	you can harvest two to four times in a green house using light deprivation techniques __________________ If you want it to rain .... Hang some buds up to dry If you want it to be windy .... Try to setup a greenhouse
	Quote

06-19-2009, 06:25 AM	#8
nomaad Senior Member Join Date: Jun 2009 Location: somewhere in the 707 Posts: 4,472	I just started pulling tarps over my two 15x16' hoophouses tonight at 8pm. We'll pull the tarps off at 8am every day. I did a lot of research and bought 2 DuraTarp Silver Super Sun Blockers from creativeshelters.com... one 40x50 and one 40x40 (i originally was going to do one 50x16' hoophouse with a lot more plants, but the sheriff came by and made me take some down)... anyhow, by no means do these tarps block out all the light. I went inside and let my eyes adjust and i could just barely see light comeing thru the tarp. Amd its 8pm... the sun is behind treees at this point in the day, so we're not even talking about direct sun. I am hopefully going to be able to get away with adding a layer of 6mil black plastic and not have to go out and buy a ton of expensive "panda" plastic... the kind you use to line the walls of an indoor grow room.
	Quote

06-19-2009, 05:43 PM	#9
SweetHempSeeds Member Join Date: Jun 2009 Posts: 54	Hi there, I run lite dep, ive got a crop at 54 days now. What ive found works best after a few years: I use a poly silver/black hay tarp from farmtek. Silver side up to reflect lite. There is a bit of lite (pinholes) in the tarps, but they work just fine. Ive not had any hermie issues in 4 years of using this tarp. On humidity, there are ways around it. One is to put the tarp on at dark, take it off when it totally dark, then put it back on before sunrise. If you have alot of air moving (fans) you can just open the ends, its much easier to close the ends at 4 am than pull the whole tarp. I live in an extremely dry area with low humidity, so I just leave the tarp on til its time to remove it. When I pull it off my humidity is in the 90's, but within 45 minutes it is back into the 30's. IMO this is considered 'humidity shock' and wont allow any type of fungi to establish itself. I think it you tried this in a humid area it would not work (leaving the tarp on and letting the humidity get so high). I also use only shdeclothe on my greenhouse frames in summer. This allows exponentially more airflow. I roll up the covers and leave them attached to the frames, and can pull them on when foul/cold weather comes in fall, to keep my buds dry. Good luck! SHS
	Quote

06-21-2009, 05:52 AM	#10
nomaad Senior Member Join Date: Jun 2009 Location: somewhere in the 707 Posts: 4,472	I considered the farmtek tarp, but it was twice the price of the Duratarp, so I went the other way. We started working with a 6mil black visqueen under the Duratarp. We pull the black plastic first in one direction, then the tarp over in the other. It is now completely dark in there- after about 5 minutes of eye adjustment there is zero visible light. d-a-r-k SHS: I don't have the experience to disagree, but the sum-total of the wisdom I have collected from large commercial black boxes does disagree that absolute blackness matters. Strains that are prone to hermaphrodism will herm (so no awesome landrace sativas) and later blooming are the reasons cited for the absolute darkness regime. I have been specifically warned against opening up for the late night. While I have not grown extennsively in N.America, I have grown in Central America. There, we use supplemental light to grow hybrids and indicas. We have found that, without a doubt, if we start to play with light cycles the process benefits significantly by imposing complete darkness during the dark part of the cycle. I still appreciate and respect your experience-based wisdom. It makes me think "I'm glad its totally dark in there, but I guess I don't have to be so paranoid that a pinhole leak is going to ruin everything." so thanks. Sooooo... 57 days in? I'm jealous. That's basically when I got back from Central America... I had this fantasy that my black box would be up a week after getting here, but it took just a wee bit longer- had to find a place and build 500ft of fencing! So, what strains? Hows it going? How much longer till it comes down?
	Quote