Question about lighting per X suggestions

Good morning everyone, I found myself wondering about something recently. So pretty much everyone will agree if you have a lets say 4x4 tent that you will need X wattage light. I’m using an HLG 550v2 for my 4x4 for instance.
The question I have is since we go by DLI or PPDF why is wattage even a thing? Going off of DLI charts I’m following I’ll theoretically never hit near my max wattage for my light. In order to maintain the DLI and PPDF throughout my grow I will more than likely never need to get to my max wattage. I’m currently at maybe 70% and going off DLI charts if anything I’ll be turning down my wattage once I get past a certain point.

So why do we do suggested wattage for tent sizes since now it’s all about Dli which I do not need near what my light can do?

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I do believe that they still provide those details so people can figure their cost of electric before and after install of lights and how much of the bill could be fluctuating from running the lights. I also believe its an industry standard to give the watts. @dbrn32 probably has the answers for you as hes our lighting expert here

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Thanks and it was just something I was randomly thinking about. I’m like man I really want to crank my light up and everyone said 450+ watts is kind of minimum for a 4x4 tent but it seems I’ll never need near that to maintain proper levels. Since I’m learning still and digesting everything I can I wanted to figure out what I was missing :thinking:

IDK, but Awesome lights for TWO 4x4x6.5 tents


Overkill or MAXIMUM coverage in one tent.
CO2?

I’ve had the same Q! I’m running 2-100W Q panels in a 20x36” tent (2 plants) 12” height from the canopy full power since week 3.


That white temp sensor is 12” from the lights so, that AM up they go by @3”. Now I’m dealing with only 4-5” height adjustment. It really is a balancing act between light intensity and nute strength and tent size. These things can grow fast, real fast…like weeds!
Here’s one for you from Nebula Haze at Grow Weed Easy: That’s right 65W and not finished growing!

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Here it is just before harvest


I think the point is, that you can stealth grow using minimal energy if you train and feed as she has done with good yields.

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What ppfd meter are you using to calculate dli? And many of us don’t use dli or vpd. Some of us push right up to just under co2 levels of lighting if the plants can deal with it. While others stay below dli numbers because some of this near useless fufu weed now days won’t handle dli. It’s also very nice to have the power to not need to crank the dimmer control all the way up in the summer months and have to deal with the heat issues. And in the winter months if you have the power one can raise the lights higher and crank the dimmer up and get enough heat to not have to use supplemental heating. Look at it this way… You want a car or truck you have to be at full throttle to go 65 mph on the hwy level ground? No, you want control. Watts, dimmer and yoyo’s are your control.

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My lights run full tilt once flipped, up to the last 2 weeks of flower. Autos get crushed full tilt after the 3rd week until the last 2 weeks. Always around 55 to 60 dli :joy::call_me_hand:

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I found that if I turned my two 240W lights all the way up I’m up over 100 DLI and I always have minimum of 18 inches above the plants.

So I use my dimmers. It IS possible to get them to 50 - 60 DLI but the lights have to be pulled up to the top of the tent for that.

You may not have to go to the top of the tent. Or just a few inches. But in the long run count your blessings. You have enough light to stay in the dimmers, keep the heat load down in the summer months and extra power to heat with in the winter if you have a proper tent height so you can go full blaze and use the heat. That’s one reason why I always do very tall enclosures/tents.

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We don’t agree, because some lights make more ppf per watt than others.

This is correct. Watts don’t matter, light energy does.

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I bought a 5x5 tent and because the Spider farmer said it was best for 5x5. Later all the youtube channels swore buy 4x4. In a panic I bought another sf4000 and now I don’t know how to judge how much light is in the tent. I need Help Help

@Spidergrow420 a 5x5 tent needs about 1000 watts if you go by the 40 watts per sq ft that’s standard practice. I have a 4 x 4 flood table and my lights are good for 5 x 5 easily. Having too much power can never hurt. That’s why most lights have dimmers.

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Thanks for the reply iknew you would know. It was just a random thought I had that hit me lol. I was also only thinking in terms of Autos not photos which others broke down some things for me. I appreciate it.

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Thanks Alot Mate

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