2K somewhere less than 2ft
Growers NEED to tell the truth on this one!!
- Thread starter Useful Idiot
- Start date
stillsmokin843
Member
Ya Useful,Open but with a reflector.I might lower my lights a little this run I got coming up.Always worried about burning,though it has never happened.Got more strains this time then in resent years.[/quote]
one rule of thumb ive always went buy is if you can hold the back of your hand (not the palm) at what ever distance you choose for 30 sec with out burning you then it wont burn the plants. so when in doubt do the 30 second test if it doesnt get to hot for your hand then it wont burn the plants. a good fan blowing across the top of the canopy always helps also.
stillsmokin843
Member
dont know why it quoted all messed up was referring to his worry of burning the plants
OK btw my footprint is like 5 1/2 x 5 1/2 with 1k I was tryin to keep at 18 inches but I guess the yeildmaster will not spread the light over that area at 18". I'm gonna raise to 22" and see what happens. Thanks for all the input so far!!
F
Fastcast
one rule of thumb ive always went buy is if you can hold the back of your hand (not the palm) at what ever distance you choose for 30 sec with out burning you then it wont burn the plants. so when in doubt do the 30 second test if it doesnt get to hot for your hand then it wont burn the plants. a good fan blowing across the top of the canopy always helps also.[/quote
Thanks man,I've been doing that for over ten years,I don't have a light meter.This is a good way to judge heat in a pinch.Safe groing
Thanks man,I've been doing that for over ten years,I don't have a light meter.This is a good way to judge heat in a pinch.Safe groing
Sooo what is your plan for the 1000??? We now have 15" in a 3x3 I really think this thread wlli end up bein very useful...Idiot out!
My plan is to veg for another 4 or so weeks with the 400 and then throw the girls into flower with the 1000. I live at very high elevation so it's already getting cold here at nights. I'm hoping I won't have to change my ventilation set up at all as I run my lights at night when the temps are naturally colder. As far as height from canopy I will probably get it as close as possible without getting too hot. With a 3x3 footprint I don't have to worry about light distribution with a 1000.
Exclusive
Member
Its a middle of the road thing. The lights (depending on the hood or lack thereof) will throw an obvious area that they cover. I keep my lights as close as possible AS LONG AS the light just hits the tent a little.
these are 1000s and they could be a bit closer but its 1.5 weeks into flower so they are stretching a few inches a day
these are 1000s and they could be a bit closer but its 1.5 weeks into flower so they are stretching a few inches a day
I run a 1kw hps in a 1.2m x 1.2m tent at 16" - 18"
What I do is move my finger up the wall in the tent and watch where it is the brightest and adjust that point about 2" below the top of the colas. Also, the last week I raise the lights all the way up, don't know why, it just seems like the right thing to do.
What I do is move my finger up the wall in the tent and watch where it is the brightest and adjust that point about 2" below the top of the colas. Also, the last week I raise the lights all the way up, don't know why, it just seems like the right thing to do.
My new adventure features two 400w CMH bulbs in a 2.5 ft x 6ft space, hung vertically with bare bulbs. Whole chamber (except floor) is lined with reflectix. 
I currently have the bulbs hanging up high because the plants have only been out of the cloner and into the coco for 2-3 days. Soon I will begin to lower the bulbs to about plant height.
The furthest any plant in my setup will be from the light (and I'm talking about the backside of the plants in the corners) is 2 feet 7 inches.
I currently have the bulbs hanging up high because the plants have only been out of the cloner and into the coco for 2-3 days. Soon I will begin to lower the bulbs to about plant height.
The furthest any plant in my setup will be from the light (and I'm talking about the backside of the plants in the corners) is 2 feet 7 inches.
overgrow00
Member
50w per sq ft is the rule of thumb for how much light is needed for your grow space...
so if you use a 1000w light and want to hit 50w per sq ft you would like a space that is 20 sq ft.
the rule of thumb has nothing to do with how far the light is away.
but for the original question:
i use 1000 watters in silverstar hoods that are air cooled. i put them 12"-18" from the tops and try to form the canopy to the light.
Hey Anti, thanks for droppin by. I see you got your disco ball hung. I thought you were kiddin.My new adventure features two 400w CMH bulbs in a 2.5 ft x 6ft space, hung vertically with bare bulbs. Whole chamber (except floor) is lined with reflectix.
I currently have the bulbs hanging up high because the plants have only been out of the cloner and into the coco for 2-3 days. Soon I will begin to lower the bulbs to about plant height.
The furthest any plant in my setup will be from the light (and I'm talking about the backside of the plants in the corners) is 2 feet 7 inches.
I've used a 600W and 1000W lamp over a 3x3 ebb/flow table.
The 1000W won hands down.
It has enough guts for a 4x4 table.
As for the height...I just put the back of my hand at the top of the canopy and if it feels hot I raise the lamp.
Works for me.
The 1000W won hands down.
It has enough guts for a 4x4 table.
As for the height...I just put the back of my hand at the top of the canopy and if it feels hot I raise the lamp.
Works for me.
My new adventure features two 400w CMH bulbs in a 2.5 ft x 6ft space, hung vertically with bare bulbs. Whole chamber (except floor) is lined with reflectix.
I currently have the bulbs hanging up high because the plants have only been out of the cloner and into the coco for 2-3 days. Soon I will begin to lower the bulbs to about plant height.
The furthest any plant in my setup will be from the light (and I'm talking about the backside of the plants in the corners) is 2 feet 7 inches.
Lol, are you having disco parties in there too?
Do some research, wattage and distance has everything to do with it. If you have one 50 watt bulb, 1 ft from 1 plant, then that is your total for that bulb. Now take 100 watt bulb, you have that 1 ft from your plants then you have 100 watt per sq ft. Now you move that 2ft out and you have 25w per sq ft. Inverse Square law, look it up.
From Wikipedia -
Light and other electromagnetic radiation
The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy (in the same time period).
More generally, the irradiance, i.e., the intensity (or power per unit area in the direction of propagation), of a spherical wavefront varies inversely with the square of the distance from the source (assuming there are no losses caused by absorption or scattering).
For example, the intensity of radiation from the Sun is 9140 watts per square meter at the distance of Mercury (0.387 AU); but only 1370 watts per square meter at the distance of Earth (1 AU)—a threefold increase in distance results in a ninefold decrease in intensity of radiation.
In photography and theatrical lighting, the inverse-square law is used to determine the "fall off" or the difference in illumination on a subject as it moves closer to or further from the light source. For quick approximations, it is enough to remember that doubling the distance reduces illumination to one quarter;[4] or similarly, to halve the illumination increase the distance by a factor of 1.4 (the square root of 2), and to double illumination, reduce the distance to 0.7 (square root of 1/2). When the illuminant is not a point source, the inverse square rule is often still a useful approximation; when the size of the light source is less than one-fifth of the distance to the subject, the calculation error is less than 1%.[5]
The fractional reduction in electromagnetic fluence (Φ) for indirectly ionizing radiation with increasing distance from a point source can be calculated using the inverse-square law. Since emissions from a point source have radial directions, they intercept at a perpendicular incidence. The area of such a shell is 4πr2 where r is the radial distance from the center. The law is particularly important in diagnostic radiography and radiotherapy treatment planning, though this proportionality does not hold in practical situations unless source dimensions are much smaller than the distance.
[edit]Example
Let the total power radiated from a point source, for example, an omnidirectional isotropic antenna, be P. At large distances from the source (compared to the size of the source), this power is distributed over larger and larger spherical surfaces as the distance from the source increases. Since the surface area of a sphere of radius r is A = 4πr 2, then intensity I (power per unit area) of radiation at distance r is
The energy or intensity decreases (divided by 4) as the distance r is doubled; measured in dB it would decrease by 6.02 dB per doubling of distance.
Hey Anti, thanks for droppin by. I see you got your disco ball hung. I thought you were kiddin.
In my thread, someone suggested a disco ball as a joke and I just happened to have one lying around in a box in my basement. So I threw it in there for the fun of it.
Fun is an integral part of this hobby. When it stops being fun, I'm done.
