Lighting, Can you get your plants to close?

[keenan878]

Ive been someone who has allways believed that the closer you can get to your plants to your lights the better. Ive been doing this for a couple years now, i have 8in ducted hoods to where i can get the plants to almost be touching the hoods themselves without an issue. ive lately been seeing that this may not be such a good idea becuase the UV-B rays could be stressing out the plants and not allowing them to photosynthisis properly. What are your thoughts on the matter?
Thanks

 

[mrbubbles]

Good question.

 

[Bannacis]

You didn't mention your light type, but if your using vented hoods with glass, i'll assume they are hid lights. yes you can be too close, raise your lights up so that it will also raise your leaves of the plant up, you want them to reach some.if they are drooping(hanging) then you are deff too low.
glass plates on your hoods do reduce some of the light some.
plus if you raise the lights you can spread your plants out alittle, crouding them is also bad.
and also alow better air flow.

 

[keenan878]

I'm running dual arc 1000's, plants are any where from an inch to a foot away from the glass. I'm running scrog with plenty of air flow

 

[Bannacis]

wowsa, yeah i would raise em up to about 18-24 inches, if you look at some of the big grows, they usually have them plus 2 feet or more from top of plants.
You don't want to stress them out with light poison,
Do a test and raise them up to 18-24 inches and watch them for a few days and see how they react. you want you leaves to reach up like 30 degrees or so.

 

[paulycali]

Only to much light during the last 2 weeks of flowering is harmful to the plants imo. They burn off the essential oils, terpenes and trichomes. Thats why its best to raise your lights during those weeks and add supplemental lighting. For ex. switching out hps bulbs for mh. Or adding Led's

 

[dankworth]

Get one of those $50 light meters. Mine got rebranded by hydrofarm.
Try to keep light values under 5500 footcandles maybe, that is what I have heard/read is a point of declining rate of return for wattage vs weight.
Can foliar to supplement enhanced nutritional demand from enhanced light values.

 

[keenan878]

so your suggesting leaving them be for now

 

[keenan878]

Get one of those $50 light meters. Mine got rebranded by hydrofarm.
Try to keep light values under 5500 footcandles maybe, that is what I have heard/read is a point of declining rate of return for wattage vs weight.
Can foliar to supplement enhanced nutritional demand from enhanced light values.

I'm to far along to foiler feed. I'm currently getting a little more then 1 and a half per light so im not to super worried about it, but if moving them higher can get me more medicine then i'm all for it. ill check the foot candles and see what it says. thanks for the info

 

[dankworth]

I'm to far along to foiler feed. I'm currently getting a little more then 1 and a half per light so im not to super worried about it, but if moving them higher can get me more medicine then i'm all for it. ill check the foot candles and see what it says. thanks for the info

I personally am fond of sixtysomething watts/ft2 for overhead. Lower watts/ft2 may be better for total overall yield for non-sealed environment.

 

[keenan878]

i'm in a sealed CO2 inviornment, have 2 12x4 ft tables, with 3 100's per table so they're covering roughly 3x4 area per lights

 

[keenan878]

i'm in a sealed CO2 inviornment, have 2 12x4 ft tables, with 3 100's per table so they're covering roughly 3x4 area per lights

so 83.3 watts per ft^2

 

[dankworth]

so 83.3 watts per ft^2

You are at 62.5 watts/ft2 average.
Sounds about right.
A lot can vary according to reflector, though.
I found 80 watts/ft2 from super sun 2's overhead to be a little too much. I enhanced light values by having reflectix walls, floor, ceiling though.

 

[keenan878]

raptor hoods and panda film walls, also 3rd run on bulbs with digital ballasts so lumens are probably down

 

[outwest]

You are at 62.5 watts/ft2 average.
Sounds about right.
A lot can vary according to reflector, though.
I found 80 watts/ft2 from super sun 2's overhead to be a little too much. I enhanced light values by having reflectix walls, floor, ceiling though.

You still running digilux?

outwest

 

[keenan878]

hortilux

 

[keenan878]

hortilux

super blue's(dual arc)

 

[dankworth]

You still running digilux?

outwest

Gonna go with plantmax this time I think. Hella cheap, good PAR values.

 

[outwest]

My concern with cheaper bulbs isn't the quality of output but rather the increased potential for failure.

outwest

 

[dankworth]

My concern with cheaper bulbs isn't the quality of output but rather the increased potential for failure.

outwest

As far as I know(and this is coming from someone who nerded out on this sort of thing way more than I did) there are a very limited number of manufacturers, and many lamp brands are identical or nearly identical. Lots of rebranding going on in the lamp industry apparently, not very much true innovation.

When I am better funded, I will try out the lamps from the guys that do the growlite og hoods. But for now, the plantmax is pretty damn affordable for the PAR watts.
I will let you know how the plantmax lamps work out.