OK, now tell your buddy to buy light movers for his 2 lights and do the test again. Also, have him turn up the light to 100% for the last 21 to 28 days before the chop.
These are the ones I use:
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So are you saying to move the lights daily or weekly around the tent? Won’t we still hit the watts vs yield ceiling still with two lights?
Will the buds foxtail @ 100% if we do that? I had some stress issues @ 100% on the first grow.
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lol…I added a link to my post to show you what I mean by a light mover. It’s not someone you hire to move your lights every few days, it goes back and forth during the light cycle throughout the grow.
The lights sits in one spot at the start and end of the rail, but only for a matter of seconds - and you control how many seconds. No hot spots. I use 1000W HPS, so…
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Sitting around for this one!
I know what yah talking about 
I just never thought of doing a test that way. If a plant gets a light to itself for 2-3 days and then it is removed arent we still going to hit the watt vs yield issue? If a plant has a light for the entire grow vs being moved on off 1/2 the grow arent we still gonna hit that ceiling?
The light(s) slowly move back and forth above your plants. There is no removing them.
I did a test last year where I grew 47 ounces under a 600W HPS, then turned it up to 1000W HPS for the last several weeks. I wasn’t testing lights or light movers, I was testing nutes - but the results are what they are.
EDIT: @Gravitys-Rainbow, here’s a link to that test I mentioned above: CLICK HERE
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Are we going by watt per sq.ft for cost purposes. I think ppfd should be looked at as well…
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I was always to believe more light means more bud . So your experiment seems to prove that .
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Agreed, but I also believe there’s an opportunity to increase yield by using the light(s) more efficiently.
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There is a stopping point. I think it’s like 1100 ppfd without co2 supplement.
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That is what I am looking for… dialed in efficiency… I guess we all are.
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I think I mentioned my use of CO2 in that thread I linked - but I’m also a big believer in using CO2 to increase yields!
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I do want to test this once i get a metal building. Did you seal a tent in plastic too to keep it in? How much does that co2 bottle cost you?
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I built a room using black and white poly. It’s sealed, and I use light hoods with duct outlets. This allows me to pull in cool air from outside the room and run it over the lights, and also pull the heat away from the lights and exhaust it outdoors.
As for the CO2, the “bottle” (50 pound tank, which actually weighs about 170 pounds empty!) is expensive, but it only costs me about $26 to get it refilled every 2 months or so.
Edit: here’s a rare photo of my room when it’s empty. You can get a rudimentary idea of how the ducting works.
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I’m gonna put this in the backlog too. That would be a great test that me and my buddy can do.
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If you don’t mind my asking, how large a room is that 50lb tank covering? I’m planning to buy one myself once I get my basement room fully sealed, and I’m curious what size I should be aiming for. Ugly that it’s so heavy… I’m guessing if I need to go all the way for a 120lb, I’d need to get it down the stairs on a handtruck, which is never fun.
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I think I’d plan to keep it on the main level and pipe it down to the grow area . Less work when it comes time to fill it.
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So simple it’s brilliant. Dunno why I didn’t think of that… I can put it in the garage and it would literally be inches away from the basement wall. Duh… I guess it’ll be a lot easier to handle than I was thinking! The one upstairs won’t be nearly as bad, that’s only covering about 300 cubic feet.
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That tank is a nightmare. It’s a long story, but I got a great deal on one that was actually 75 pounds (and it was full!), and traded it at my gas distributor for the 50 pound tank. If I had to buy one, I’d pay the extra and get the aluminum one. That will solve all the weight issues.
Regarding the weigh issues - it’s hard to explain just how difficult it is to move that thing up and down stairs WITH a handtruck. In fact, I stopped using a handtruck to get it downstairs, and instead, use a long ramp with rails on the sides and just ease it down.
As for the room size, I think I’ve mentioned it elsewhere, but it’s approx 10x12 (feet). For a similar sized room, you could get away with a 20 pound tank. You’ll need to get more refills, and the refill for a 20 pound tank is only about $5 less than the 50 pounder.
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