Is there really such a thing as "too much light"???

[Corvette kidd]

assuming you are using HID which most people are, 50w per square foot is a good mark to shoot for. 75w per square foot might be over saturation which is not good. This might change if you are for example using 50w per square foot of HPS and 25 w of MH or FS light, since they are on opposite ends of the spectrum. remember plants do not care about lumens. lumens are a measurment of visible light which is mainly green on the spectrum and is the only part of the visible spectrum they cannot photosynthesize. This is why the discussion of PAR and umol's/PPFD is so important. I am just trying to put it in terms that people can understand without spending all day on google reading about how to calculate their PPF. So 800w in a 4sq ft space is, um how should I say... overkill, try maybe a 150w hps or flourescent lights to avoid cooling.
really 4 square feet? did I read that right?

Yes you did read the 4 sqft right haha. Ive already built the led panel and installed it in my mini tent. i have 12 vero29's pulling 805 watts from the wall lighting up a 4 square foot area. My only problem so far is that my sfv is taking in wayyyyyyyy more calmag than usual, and ive had to increase my feeding program all around

 

[febisfebi]

Have you grown the SFV in a different lighting setup? SFV is a big producer, so it using a lot of nutrients is not neccesarily a bad thing, unless it is being caused by over saturation. I'm not sure if over saturation is possible using led's and cfl's, because of their limited spectrum, but thats an awful lot in a small space. usually over saturation comes from HID setups, but I would tone it down regardless, especially because the power draw of led's and cfl's is way lower than HID lighting, thus making your over saturation more of a quadruple saturation situation. Excessive lighting will not help you, and is not just bad for the plant, but a huge waste of power, and bad for your wallet, and uh the planet. Use enough lights to get proper coverage for your plants. Its easy enough to tell just by looking, but in your case might be one led and a couple cfl. If you decide to scale up your footprint, bring in the extra lights. But remember 50w per square foot. and when using non HID lighting such as cfl or led, that number should likely be cut in half.

 

[Dr. Who]

Have you grown the SFV in a different lighting setup? SFV is a big producer, so it using a lot of nutrients is not neccesarily a bad thing, unless it is being caused by over saturation. I'm not sure if over saturation is possible using led's and cfl's, because of their limited spectrum, but thats an awful lot in a small space. usually over saturation comes from HID setups, but I would tone it down regardless, especially because the power draw of led's and cfl's is way lower than HID lighting, thus making your over saturation more of a quadruple saturation situation. Excessive lighting will not help you, and is not just bad for the plant, but a huge waste of power, and bad for your wallet, and uh the planet. Use enough lights to get proper coverage for your plants. Its easy enough to tell just by looking, but in your case might be one led and a couple cfl. If you decide to scale up your footprint, bring in the extra lights. But remember 50w per square foot. and when using non HID lighting such as cfl or led, that number should likely be cut in half.

I like this guy! He uses the term "Saturation"! ( I really liked your posts to the CMH lighting thread and am looking at that whole pdf closely!)

If you question light saturation points in C3 plants, you should all google "light saturation point in C3 plants" Read more then one result too.

YES is the answer.

If you wonder what happens at that point the plant reduces photosynthesis and begins to change on the cellular peptide level to actually protect it's self from the intense light. This is normal in outdoor and indoor plants with high light intensity. At night or at lights out the plant reverts or changes back to it's sunrise condition and the whole thing starts over.....
The use of Co2 will slow this "need" to protect it's self by around 30% and that's the increase in yield from Co2 use.....If your lighting is not intense enough. The use of Co2 is not effective or at least less effective, as the light intensity is critical to supplemental Co2 effectiveness.

 

[febisfebi]

very true, and without proper ventilation, your c02 levels will go down to the point where over saturation occurs when it otherwise wouldnt, and photosynthesis slows down to a quarter of normal rates. So you need to blow some fans around, preferably bring in some fresh air from outside. This is assuming you are using something reasonable like 50-60w per square foot. if you really only have 4 square feet, you need to make it taller and do a vertical grow. then you can spread those lights around a tower in the middle, and therefore increasing your light footprint, while keeping your square footage the same, and not fry your plants.

 

[ttystikk]

Yes you did read the 4 sqft right haha. Ive already built the led panel and installed it in my mini tent. i have 12 vero29's pulling 805 watts from the wall lighting up a 4 square foot area. My only problem so far is that my sfv is taking in wayyyyyyyy more calmag than usual, and ive had to increase my feeding program all around

I'm planning to use that same 800W to light 16 CXB3590 and cover 24 sq ft. I'll have over 800 PPfD, comfortably over half the maximum.

I'm subbed cuz I wanna see pics of smoked pot plant, while it still has roots in the ground lol

Seriously, 200W per sq ft? Of COB LED?!