slow growth with t5 lights

ufcd1000

Active Member
growth on these plants has basicly stopped. i'm using a 4' 4 bulb t5 light. these plants have had major stress but still grew ok until 2 weeks ago. i've had the lights as close as 2" now at 6". anyone else seeing this with t5 lights or is it something else.
 

1982grower

Well-Known Member
actually check out my thread
https://www.rollitup.org/indoor-growing/162364-lowryder-2-under-540watts-t5.html

i have had the best grow of my life with t5hos. mine are growing faster than i've ever seen. it must be the stress. put the lights as close as possible. its the stress and they'll get over it. and yes i've used hps a thousand times to anyone out there. mine work great check them out. sorry about the stress but its not the lights. i flower even with mine.
 

Twistyman

Well-Known Member
T's work fine for me............ How old are they (plants) and are they approaching flower time yet...??
 

1982grower

Well-Known Member
damn guys good flouro support. very rare. many beginners use 10 watts of cfl and fail then give flouros a bad name. give any newb that failed with flouros a 70 watt hps and then watch it smoke their plant for them(burn). if hps were the price of cfl there would be just as many failures. the guy who buys a 1000 watt hps for 500 bucks have researched and expects results. most kids go get some 5 dollar flouros and prob don't even finish the grow. good luck always. may the force be with you
 

UserFriendly

New Member
damn guys good flouro support. very rare. many beginners use 10 watts of cfl and fail then give flouros a bad name. give any newb that failed with flouros a 70 watt hps and then watch it smoke their plant for them(burn). if hps were the price of cfl there would be just as many failures. the guy who buys a 1000 watt hps for 500 bucks have researched and expects results. most kids go get some 5 dollar flouros and prob don't even finish the grow. good luck always. may the force be with you
Werd. It's all about paying attention to the plant.

T5 nug..........

 

1982grower

Well-Known Member
yes obviously matched colours compared. can't compare diff colours. its weird eh? you wouldn't think it. but they are all close and t5ho makes almost the same lumen output as the t5 regs and t8 but much denser light so = more penatration. even though t8 are so efficient there size does not allow you to consentrate enough light per square foot. it is wierd though.
 

UserFriendly

New Member
yes obviously matched colours compared. can't compare diff colours. its weird eh? you wouldn't think it. but they are all close and t5ho makes almost the same lumen output as the t5 regs and t8 but much denser light so = more penatration. even though t8 are so efficient there size does not allow you to consentrate enough light per square foot. it is wierd though.
Lumens are for human eyes; photosynthetically active radiation (PAR watts) are what do it for plants. As for penetration, the light stops where the leaves start; a 1kW HPS is no better than T12s in that regard, but because HIDs are so intense, you can keep them farther away from the plants, yet still cover a large area. Fluoros kick ass in spectrum (PAR).
 

1982grower

Well-Known Member
yes but with flouros par are all very high and usually the same. my 10000k 32watt t8 bulb makes 2700 lumens with par of 93 i believe. a t5ho 10000k bulb par 93 makes 4850 lumens. At the same pars my list in that order still applies. most flouros have a minimum of 80 par so it is not neccessary when comparing flouros. very miniscule amount of par diff between flouros
 

UserFriendly

New Member
I do believe you are thinking of CRI (color rendering index). PAR is based on the wattage of the lamp. It would be physically impossible for a 32 watt CFL to put out 93 photosynthetically active watts of radiation, dig?
 

AeroKing

Well-Known Member
As for penetration, the light stops where the leaves start; a 1kW HPS is no better than T12s in that regard, but because HIDs are so intense, you can keep them farther away from the plants, yet still cover a large area.
Sorry, UF, but I gotta disagree with you there.

I read an extremely lengthy and scientific article one time that described how a certain (I think like 80%) of light either passes through or is reflected by the leaf. It explained that you can't really see it because of the spectrum...
The rate by which it will do this is described as something like "light pressure", which is basically like saying "penetration".
We can roughly measure this phenomenon as lumens to get an idea of how much "pressure" is involved. As the initial lumens from a source of light increases, it gains the ability to push farther and through more matter.
So, a 1000w light will penetrate deeper into a thick canopy, keeping leaves productive and lush, where as a floro cannot and the inside of a thick canopy shrivels away as the plant decides to focus on growth where it does get light.

Of course, I, myself can't verify any of this and apologetically, I don't have a link to the article. To me it seems to make sense, so I'm sticking with that view for now.

UF, I'd rep ya, but I gotta spread some around first...
 

UserFriendly

New Member
Sorry, UF, but I gotta disagree with you there.

I read an extremely lengthy and scientific article one time that described how a certain (I think like 80%) of light either passes through or is reflected by the leaf. It explained that you can't really see it because of the spectrum...
The rate by which it will do this is described as something like "light pressure", which is basically like saying "penetration".
We can roughly measure this phenomenon as lumens to get an idea of how much "pressure" is involved. As the initial lumens from a source of light increases, it gains the ability to push farther and through more matter.
So, a 1000w light will penetrate deeper into a thick canopy, keeping leaves productive and lush, where as a floro cannot and the inside of a thick canopy shrivels away as the plant decides to focus on growth where it does get light.

Of course, I, myself can't verify any of this and apologetically, I don't have a link to the article. To me it seems to make sense, so I'm sticking with that view for now.

UF, I'd rep ya, but I gotta spread some around first...
No shit? Yeah, that makes sense; I can't see the PAR anyway. Good point AK.
 
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