Large Green House Light Deprivation Design

[monstacropn]

I have a 40 foot long & 20 foot wide industrial tent frame. Where I'm located, right next to my grow area is a huge light for a parking lot, and this light made my crop stay in veg until December. So my request for advice is what would be the best route for light deprivation "total black out"? like:
1: whats the best place to get poly or vinyl black out material?
2: If anyone has dealt with a situation like mine(blacking out 40' long greenhouse, please tell me any advice
3: Because our plants do so well with 70 to 50% of sunlight should I look at automated set up , windows or manually roll it up n down for 2 months?
4: Using poly I'm not sure how thick to get it; our whether here in northern Cali is hot n dry most the season but there can be some strong winds?

Thank you for reading my post and advice is greatly
appreciated, Scott

 

[Jack og]

Hey, I work for a commercial grow and we have tried the most expensive to the most exotic to land at the Homedepot Black 6mil poly. It performs as good, drawback, it’s has a polystyrene smell that we leached out via “exposure” set it up in a non used room to “air out”. Other then that, this plastic rocks and it’s cheap as hell.
We have it on guide wires, with roller blocks on a “”A” frame setup, at 8’ intervals, with a rope to use as a puller, so we open it up tops, sides a permanent blackout, with door end like a shower curtain, with over lapping pcs. Once closed up, we get no light leakage but we don’t have any outside lighting to interfere, so for your situation you may have to try out methods that works best to keep that light out.
Time frame depending on breed, typical light dep 12/12 is about 9-12 weeks or if checking outhe trichs for that perfect cloudy to amber ratio. There are many threads here on time V harvest times

We have 67 200ft long by 25ft wide houses and we use Homedepot 6mil poly on the regular. And 100% light dep is always required for flower 12-12 cycle or you risk Re-veg or hermies