charlesweedmore Posted May 19, 2009 Share Posted May 19, 2009 PUTTING FANS IN THERE TO COOL THE LIGHTS IS GOOD BUT LOWERING THE LIGHTS WILL ALSO CUTT LIGHT SPREAD TO THE REST OF THE SUROUNDING AREA AS WELL TAKE THIS INN MIND IF YOU HAVE A FEW PLANTS IN THE ROOM TOKEIT that is true mate .light wont spread efficiently if you keep it too close . for instance i keep HID 25- 30 cm away from canopy. in fact i can put closer my light without burning but then light couldnt get at other plants Link to comment Share on other sites More sharing options...
Guest 2hi2try Posted June 15, 2009 Share Posted June 15, 2009 i can rest my nuts on my 600w cooltube Link to comment Share on other sites More sharing options...
Guest BioBuzz Posted June 15, 2009 Share Posted June 15, 2009 :ouch: £50 says you cant Link to comment Share on other sites More sharing options...
grooving Posted June 15, 2009 Share Posted June 15, 2009 Hopefully this is related to this thread...With a heat shield on an adjusta shade my dual spectrum 400w (+digi ballast) is about 240mm (9") away and my hand is ok under the light. Problem is after reading lots on this here site I'm still not sure whether the potential lumens lost from using the heat shield are made up for in light intensity due to the lighting being closer? Or should the heat shield/super spreader be an emergency measure combined with some LST when you run out of headroom? depends, if you have a small floor area, you'll be able to get your lampshade closer and you'll want the heatshield to protect your plants, if it's further away, light is lost to the walls. if you have a larger area then you'll need your shade further away to cover the area better, and may or may not still need the heatshield. a heatshield should only be used if it's needed, not just to get the shade closer to the tops of your plants, as has been said, you want even coverage more than you want high intensity from having your lamps too close Cheers Scraglor. I have 1m2 with an adjustashade. I have it at around 50cm as per the OP's advice. Be nice to see the differences, heat-shield versus no heat-shield. Surely some lumens are lost/absorbed by the shield? Link to comment Share on other sites More sharing options...
scraglor Posted June 17, 2009 Share Posted June 17, 2009 (edited) yeah, each time the light is reflected a small portion of energy is lost, so the portion of light that bounces off the heatshield, loses around 5% of it's energy (if the heatshield is for instance 95% reflective) then another 5% of this is lost off the reflector before reaching the plants, although in the real world, this is still quite a small amount of lost energy. like i said, the real aim is to get the lamp as close as possible, whilst maintaining even plant coverage, if this requires the lamp to be so close that the tops would burn, then get a heat shield, but 9 times out of 10 i'd say this isn't the case and you'd be better off just keeping your lamp at a sensible distance Edited June 17, 2009 by scraglor Link to comment Share on other sites More sharing options...
Randalizer Posted June 17, 2009 Share Posted June 17, 2009 but 9 times out of 10 i'd say this isn't the case and you'd be better off just keeping your lamp at a sensible distance Link to comment Share on other sites More sharing options...
CptSmash Posted August 17, 2009 Share Posted August 17, 2009 I am confused i have 400w digi about 12 inches away from the top of my plants, if I move my light UP? the spead of light will be better but less? also have 44 watts per square foot. just ordered the lightwave diamond grow from greens and then read what I hadhave (B.A.L) was/is a top make ffs but it is an all in one job and space is tight, hence the lightwave.. reading the yields here I am even more determined to increase my last yeild (4oz from 6 plants) :rofl: and to be honest I don't know if I am fucking up with the distance of my light.. is it as close as one can get it, or adhere to the recommendations? doing my nut in, so it is. plus is it okay to whack seedlings straight under the hps? If the inverse law doubles the light every six inches surely that is a good thing? Link to comment Share on other sites More sharing options...
KC Posted August 17, 2009 Share Posted August 17, 2009 12 inches isn't too far off for a 400, you can get them much closer than 600's i find. But yes the lower you move the light down the less spread you have, but more intensity as it has. Yes seedlings can go under the hid but start them a bit futher away as it'll toast em other wise. Link to comment Share on other sites More sharing options...
lazi Posted August 17, 2009 Share Posted August 17, 2009 Like many, I use a 600w to cover 4' x 4'. If I get the bulb say 12" from the canopy, that's just for the middle plants. The plants at the edges are 2'+ from the bulb. Doesn't this suggest that I'll get an uneven grow? In practice I use a parabolic reflector. (Umbrella more like.) The bulb is vertical and almost all the light bounces at least once before hitting the plants. I get a very even canopy due to even lighting but obviously 'waste' a lot of lumens. Which is best? For convenience an even canopy is way better than an uneven one but yield? I'm not sure. How could we test this? Link to comment Share on other sites More sharing options...
CptSmash Posted August 18, 2009 Share Posted August 18, 2009 Thanks for the clarification guys, waiting for new light to arrive, have read here that there is a big payload heat wise with the Diamond reflector, hope that isn't the case, how many lumens per square is the ideal? I think in growroom tools it said I had over 5000 lumens per square foot, I may need to raise the light because of heat issues but the lumens at the plant, drop to 23,555 from 53,000 so moving the light up another 6 inches is going to cost me lumens? Also if I left the cupboard door ajar, would lumens escape? leaving the door slightly ajar fills the room with light, but I am thinking the main bulk of that light is still going on the plants? by leaving my door open do i effectively increase the size of my growroom and decrease the effect of the hps? so basically door open or shut. Sorry if this is a dumb question but I want to wrap my head around getting the most out of my light. Ta. Cpt. Smash. Link to comment Share on other sites More sharing options...
scraglor Posted August 19, 2009 Share Posted August 19, 2009 yes leaving your door open you will lose some light, but if the room over heats because the door is closed, you'll lose a lot more yield from excessive heat than you'll gain from the relatively small portion of light that would be reflected back towards your plants if you had the door closed Link to comment Share on other sites More sharing options...
Terra-ist Posted December 6, 2009 Share Posted December 6, 2009 why is it overkill? more light = more bud!! i have 84 watts per sq foot T1 I have 37w/sqft and hit 20oz plus every time but i wouldnt be confident of hitting 45oz if i upped it to 74w Sometimes space limits what you can possibly do so yes sometimes you can go overkill Its like me saying if i put 3x600's in there i'd get roughly 70oz,if you see what i mean Owd Yeah i see what you mean "rule of diminshing returns" so in a 1x1 grow tent would i be over doing it if i were to use a couple of 200w enviros as "supplemental" to 600w giving me 92w sq ft.?? Link to comment Share on other sites More sharing options...
ALLBUDZ Posted December 7, 2009 Share Posted December 7, 2009 (edited) nice, tip. just to add to it; the best practical lighting combination for flowering is generally considered to be a 2:1 ratio of hps:mh.the mh helps make he buds moe dense and solid than with solely hps lighting. See when peeps say add an M.H. to the area, how is that done. If you hang a 600hps with a 400mh they are different heights so the 600 is shaded plus one side gets either of the other. Hows it done in a tent when you cant use a light mover. Anyone had this problem before in a tent, if so how did you sort it. If said to move plants, how often etc to get an even spread.. thanks... I know this is an old post but does anyone know the answer to this question?, It might be there amongst the 103 replies, but I aint the time to read them all... Cheers.... Now 104 replies!! Then hopefully 105 with an answer..... Thanks.... Edited December 7, 2009 by Scooby's Doobies Link to comment Share on other sites More sharing options...
scraglor Posted December 8, 2009 Share Posted December 8, 2009 you just hang em both at the same height. a 400w is still effective at the same height that a 600w is effective, the only difference is you can get a 400w maybe 3" closer..... which is bugger all Link to comment Share on other sites More sharing options...
KC Posted December 8, 2009 Share Posted December 8, 2009 See when peeps say add an M.H. to the area, how is that done. If you hang a 600hps with a 400mh they are different heights so the 600 is shaded plus one side gets either of the other. Hows it done in a tent when you cant use a light mover. Anyone had this problem before in a tent, if so how did you sort it. If said to move plants, how often etc to get an even spread.. thanks... I use open ended reflectors, so when i've ran two lights in my flower area (600+400) i face them to each other, that way one can be lower than the other with minimal light blockage. Obviously the plants in the middle get the best spot as they have the overlap from the two lamps. Moving plants every day can be tiresome so just rotating is a comprimise, even moving them about each week will be good though, meaning each plant has a go in the 'good bit' Link to comment Share on other sites More sharing options...
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