Bright intense centralized light vs cool dimmer light spread out.

[drew13ee]

Has anyone heard of any research done on light intensity,in relation to heat,in relation to distance from plants?
I'm asking because I recently started my first grow on 30 years. And noticed that with low wattage leds, i could keep the light as close to the plant as possible, and the plants were doing awesome.
I got a bigger light. Had to keep it further away. And the plants didn't seem to be growing as well.
I have a theory that maybe less intense light spread out, might be more advantageous than more intense light that is more centralized.

 

[THCosmic]

I also have the same theory and would love to know if there have been studies on this as well. I always tend to think in terms of wattage per square foot. If you maintain the same wattage per square foot, the grows should be similar, even if light count differs. Multiple lights will also have better penetration since there will be more angles for the light to reach lower parts of the plant(s). Max temp of each individual lower wattage light would be lower than a single higher wattage light, so maintaining ideal temps would be easier. I can only see benefits to using more lights over a single light which is why I also have this same thought.

 

[LoveGrowingIt]

Has anyone heard of any research done on light intensity,in relation to heat,in relation to distance from plants?

Yes. Light is frequently discussed on forums. Also, Dr. Bruce Bugbee does academic and corporate research and has numerous youtube videos on many topics related to cannabis growing. Then there's always Google, of course.

I'm asking because I recently started my first grow on 30 years. And noticed that with low wattage leds, i could keep the light as close to the plant as possible, and the plants were doing awesome.
I got a bigger light. Had to keep it further away. And the plants didn't seem to be growing as well.
I have a theory that maybe less intense light spread out, might be more advantageous than more intense light that is more centralized.

As you theorize, keep in mind the optimal light for a plant depends on the plant's life stage. That said, I run my lights in accord with your theory. I keep my lights at the top of the tent, which is the maximum distance from the plants. I haven't had to turn up the power. Indeed, it's quite the opposite.

 

[LoveGrowingIt]

I also have the same theory and would love to know if there have been studies on this as well. I always tend to think in terms of wattage per square foot. If you maintain the same wattage per square foot, the grows should be similar, even if light count differs. Multiple lights will also have better penetration since there will be more angles for the light to reach lower parts of the plant(s). Max temp of each individual lower wattage light would be lower than a single higher wattage light, so maintaining ideal temps would be easier. I can only see benefits to using more lights over a single light which is why I also have this same thought.

Are you assuming constant efficiency across all power levels?

 

[THCosmic]

Are you assuming constant efficiency across all power levels?

Thinking about that I think I should rephrase my initial thoughts to "I always tend to think in terms of lumens per square foot". My assumption is that one 600w light will produce the same lumens as six 100w lights.

 

[LoveGrowingIt]

Thinking about that I think I should rephrase my initial thoughts to "I always tend to think in terms of lumens per square foot".

Well... Lumens isn't a commonly used unit of measurement for growing plants. Growers are more likely to use photosynthetically active radiation (PAR) or daily light integral (DLI). I was referring to the efficiency of the lights themselves. That is, is the light as efficient at 10% as it is at 50% or 90%? The units of measurement might not matter, but it helps to speak the same language.

My assumption is that one 600w light will produce the same lumens as six 100w lights.

That's a logical assumption. I'm leery of assumptions, though. That's why I mentioned efficiency of the light itself. Does the assumption hold true across all power levels? I don't know that answer to that one.

I tend to be skeptical about lights. That's because I question how much is gained by running high-power lights. Nevertheless, many growers assign significant importance to using a lot of power. I'm sure that depends on desired outcomes. For our personal use, a 250-watt light is more than adequate. I have power meters on all my lights, and rarely do I use more than half the rated wattage of a light. I'm currently finishing vegetation in a tent and the PAR Level (PPFD) is about 450, which is in the middle of the recommended range of 250 to 600. The light is using 80 watts.

To measure light, I've been using the Photone app for my phone. The app itself is free (or it was the last time I downloaded it). A diffuser might be required that costs about $30. Their website has useful information about light. Here's the page I cited for the PAR levels.

Common PAR Levels for Cannabis

Identifying the ideal PAR levels is quite complex and dependent on a lot of influencing factors. This article provides and overview, recommendations, and signs to detect if your cannabis plant has too much or too little light.

growlightmeter.com

 

[THCosmic]

Well... Lumens isn't a commonly used unit of measurement for growing plants. Growers are more likely to use photosynthetically active radiation (PAR) or daily light integral (DLI). I was referring to the efficiency of the lights themselves. That is, is the light as efficient at 10% as it is at 50% or 90%? The units of measurement might not matter, but it helps to speak the same language.

Yeah, I figured that out earlier today, lol. Started to dig deeper after this and learned about PAR meters and a few phone apps. Downloaded one of the apps and now I'm just waiting for my lights to go back on to test it out.