how close is to close
- Thread starter frankobud
- Start date
As close as possible without burning your plant tops and being able to cover the area that your plants are in. I keep 4"-6" away, but I don't have a large area to cover with my light and my hood is air cooled.
Pine
Put your hand at canopy level under the light to determine how warm it is. If it is too warm for your hand, its probably too warm for your plants. And watch for light bleaching on the leafs.
Plenty of good info on hermies on this site. Try the search option.
Plenty of good info on hermies on this site. Try the search option.
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danimarie193
i do a hand test. put my hand at the top of the plant to see how hot it is. its simple but works for me.
depending on temps, reflector geometrics, air cooling, these variables all change.
most gardens can easily handle 1000w uncooled at 24" if the room itself is climate controlled. I ran un cooled at 10" from some of my canopy w the proper nutrition. a few leaves taco'ed but it certainly didn't affect anything adversely.
uncooled horizontal wing or box style reflector:
1000w: 18-24"
600w 12-18"
400w 8-12"
unless your tom hill, and have the space to throw 64 plants under an 8x8x8 area, with a parabolic hood, vertical bulb and let em go...
box hoods are extremely poor in design for the most part. I have em. use em from time to time. I use what I got.
When it comes to air cooled reflectors, it's all about getting the bulb as close to the canopy as possible. inverse square law proves that getting a bulb 1' from the canopy is far more intensity than 2'. the problem is light dispersion from various sizes and geometrics provide different patterns. some throw deep and narrow, while others throw short n wide. I like tubes. they throw really wide so I can get them 1' over my canopy and cover a good amount of a 4x4 pattern. tubes have the best airflow so less CFM is needed to cool them.
I have used rails to help bring lights closer to the canopy as well. if a light is constantly moving, its going to be difficult to heat up.
If you see heat stress it's too close.
the only place I ever get this supposed bleaching is directly under a bulb on a plant or two that were directly under arc tube of horizontal hung bulbs. if you are seeing "light bleaching" on everything, I would suspect a lockout or deficiency of some sort. the sun doesn't bleach outside. but the bulb has a serious hot spot over a very concentrated area. that or the reflective material has too many rigid bends that create multiple hotspots over a canopy. these to me are the only source capable of bleaching. 9 times out of 10 chlorosis occurs when the rhizosphere is incapable of nutrient uptake do to a lockout of minerals or major PH fluctuations, or disease/infestation.
reckon
Member
I have an air cooled 1000watt and I keep it: minimum=14" maximum=20"
I have a fan that blows across the plant tops, day time temps at the tops never exceed 82f, and mostly it's in the upper 70's
I only get bleaching if I get lazy, or don't pay attention and don't raise the light when I should.
that's probably WAY closer than most would suggest for a big light like that, but it works for me.
I have a fan that blows across the plant tops, day time temps at the tops never exceed 82f, and mostly it's in the upper 70's
I only get bleaching if I get lazy, or don't pay attention and don't raise the light when I should.
that's probably WAY closer than most would suggest for a big light like that, but it works for me.
When I use a 400HPS, it hangs 2-6" above the canopy, depending. My 600s sit ~10" above the canopy. All hoods are air-cooled.
Simon
"what would be to high of a temp?"
keep the air circulating, and tops of the plants <90deg F, and you should be ok.
general distance guidelines.
1kw: 12"-18"
400w- 6"-12"
This chart is all over the net and a very good frame of reference for light intensity, distance:
http://www.thctalk.com/gallery/data/500/medium/120051028323-Foot-CandleChartHPS559W.jpg
keep the air circulating, and tops of the plants <90deg F, and you should be ok.
general distance guidelines.
1kw: 12"-18"
400w- 6"-12"
This chart is all over the net and a very good frame of reference for light intensity, distance:
http://www.thctalk.com/gallery/data/500/medium/120051028323-Foot-CandleChartHPS559W.jpg
richirich_99
Member
i use a 400 watt in a cheap air cooled reflector and keep it 4-10" from the top, some tall tops may get a lil closer, and since i run perpetual i just lift the new girls to about 10-14" away. i also have lots of air circulation in the tent with clip in fans.
I have a DR60 with 4 fans in each corner and one blowing directly over the hot spot under the bulb. air flow is key for geting the light close without any adverse heat problems.
I have a DR60 with 4 fans in each corner and one blowing directly over the hot spot under the bulb. air flow is key for geting the light close without any adverse heat problems.
Skunklover
Member
Chart is gone.
