Lighting DLI and PPFD

Joined
Dec 18, 2017
Messages
5
Reputation
0
Reaction score
20
Points
0
In the past few years ppfd has entered into the mainstream as a term that all growers should be familiar with. There's tons of write ups online about optimal ppfd levels, so I'll spare you all with repeating it here. More recently, and with less attention, the topic of DLI has been discussed in a few places. The idea behind dli in layman's terms is essentially that a plant can only take in so much light in any given period of time. We know there is such a thing as too much and too little light as measured by intensity using a par meter. Another part of the equation factors in dli in conjunction with par however.

The idea of what is optimal ppfd in a given space in generally discussed as it pertains to a 12/12 photo grow. As the math scales proportionately, we can essentially cut our ppfd in half as used in a 24/0 auto grow. For example, it would appear then that 500 watts on a 24/0 cycle is exactly equivalent to 1000 watts on a 12/12 cycle, and will produce the same results.

There's little talk on this forum on this topic, so I'd urge everyone who's unfamiliar to start poking around the web. I read some great posts from people I trust on other forums, and I can't seem to find them now but will update with links as soon as I do. I'd also like to hear your thoughts and if you have any experience playing with light levels in auto grows.
 
Excellent post! I've been looking at this information for a while now. The debates are endless on how long to run our lights as there is no definitive information currently. It has given me cause to wonder how light period vs dark period plays into this for autos. a friend and I have an on going discussion on this. Maybe the research into DLI will eventually give us an answer.

I've been wondering since moving to high power LED lighting, how much is enough. Because for all the talk of 50 watts/sq ft we ares seeing some fantastic, low power grows. Which begs the question, how much is enough?



In the past few years ppfd has entered into the mainstream as a term that all growers should be familiar with. There's tons of write ups online about optimal ppfd levels, so I'll spare you all with repeating it here. More recently, and with less attention, the topic of DLI has been discussed in a few places. The idea behind dli in layman's terms is essentially that a plant can only take in so much light in any given period of time. We know there is such a thing as too much and too little light as measured by intensity using a par meter. Another part of the equation factors in dli in conjunction with par however.

The idea of what is optimal ppfd in a given space in generally discussed as it pertains to a 12/12 photo grow. As the math scales proportionately, we can essentially cut our ppfd in half as used in a 24/0 auto grow. For example, it would appear then that 500 watts on a 24/0 cycle is exactly equivalent to 1000 watts on a 12/12 cycle, and will produce the same results.

There's little talk on this forum on this topic, so I'd urge everyone who's unfamiliar to start poking around the web. I read some great posts from people I trust on other forums, and I can't seem to find them now but will update with links as soon as I do. I'd also like to hear your thoughts and if you have any experience playing with light levels in auto grows.
 
Excellent post! I've been looking at this information for a while now. The debates are endless on how long to run our lights as there is no definitive information currently. It has given me cause to wonder how light period vs dark period plays into this for autos. a friend and I have an on going discussion on this. Maybe the research into DLI will eventually give us an answer.

I've been wondering since moving to high power LED lighting, how much is enough. Because for all the talk of 50 watts/sq ft we ares seeing some fantastic, low power grows. Which begs the question, how much is enough?

What kind of information would be needed to provide a better answer to that pop?
 
I believe we have 3 threads with the same title header DLI and PPFD open. Not sure if we just need to condense it to one thread. @pop22 @Son of Hobbes
 
I've posted this link elsewhere, I don't know if it is accurate or not so don't shoot me, but you can see the parameters you can fill in from colour, even wavelengths for blurple strips, size of lamp, height from plant, and so on, and it will tell you what your DLI, PPFD, etc, is.

Y'all might find it useful in this respect.

http://dev.edman007.com/~edman007/pub/par-dli-cal.html
 
Back
Top