how close should hps light be to plants??

lynamfamily4 · 07-09-2010, 10:17 PM

i'm going to start flowering in a week or maybe even 2marrow i don't know i just do it as i go lol i got a 400 watt hps setup how close to plants should it be placed??? farmergiles i know you know lol thanks

stoneric · 07-10-2010, 06:00 AM

Depends. If your lite is air cooled it can be closer. If you have a fan between the canopy and lite it will help. I have an air cooled 400W with a fan between it and the canopy and I keep it about 10-12 inches from the top with no problems. As always, use the back of your hand as a guide.

lynamfamily4 · 07-10-2010, 09:55 AM

ok thanks and yes i think i may be air cooled i know the ballast is built in it? but i will have fan between. do you think i should also have another fan on the plants them selves??

farmergiles · 07-10-2010, 02:19 PM

I suspect your light is not air cooled (see pic at bottom).
Having the ballast connected to the light is not the best configuration for keeping temps under control because the heat from the ballast goes right into the growroom. However that is not a problem as long as you have sufficient ventilation (ie plenty fresh cool air coming into the growspace). But remote ballasts are better.

If you are starting with freshly rooted clones I'd recommend starting 3 feet away and moving gradually closer to about 1 foot providing temperature does not get out of hand.
If you had larger plants I'd say start a bit closer.
A thermometer is helpful, the temp at the canopy doesn't want to go much over 30 Celsius.

But like stoneric says the best test is to hold the back of your hand up to the light and see how it feels.

Always wear uv protective shades in proximity to hid lighting.

Air cooled light below

stoneric · 07-10-2010, 02:27 PM

If your ballast is built into your lite, it will be hot. Air cooled lites come with fittings on each end for ducting although they sell kits to add to conventional lites to make them air cooled. Your fan or fans should be situated between your light and plants canopy catching just enough of your canopy to keep a continuous fluttering of the top of the plant. You don't want it directly at the plant or to low, which might dry out your medium.

stoneric · 07-10-2010, 02:28 PM

Damn, I'm a slow typer.

lynamfamily4 · 07-10-2010, 02:39 PM

i created a new thread with pics and details

07-09-2010, 10:17 PM	#1 (permalink)
lynamfamily4 YaHookan Join Date: Oct 2009 Posts: 59 Thanks: 47 Thanked 5 Times in 5 Posts	how close should hps light be to plants?? i'm going to start flowering in a week or maybe even 2marrow i don't know i just do it as i go lol i got a 400 watt hps setup how close to plants should it be placed??? farmergiles i know you know lol thanks

07-10-2010, 02:19 PM	#4 (permalink)
farmergiles Yahookan Join Date: Sep 2006 Location: Sick of the hatred and the lies Posts: 7,807 Thanks: 2,285 Thanked 3,750 Times in 2,554 Posts	I suspect your light is not air cooled (see pic at bottom). Having the ballast connected to the light is not the best configuration for keeping temps under control because the heat from the ballast goes right into the growroom. However that is not a problem as long as you have sufficient ventilation (ie plenty fresh cool air coming into the growspace). But remote ballasts are better. If you are starting with freshly rooted clones I'd recommend starting 3 feet away and moving gradually closer to about 1 foot providing temperature does not get out of hand. If you had larger plants I'd say start a bit closer. A thermometer is helpful, the temp at the canopy doesn't want to go much over 30 Celsius. But like stoneric says the best test is to hold the back of your hand up to the light and see how it feels. Always wear uv protective shades in proximity to hid lighting. Air cooled light below Attached Images __________________ Cultivate a stoic calmness *Fuck the Monkeys* Every Kind of Vice

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

07-10-2010, 06:00 AM	#2 (permalink)
stoneric bougeman Join Date: Aug 2004 Posts: 5,646 Thanks: 704 Thanked 1,512 Times in 1,067 Posts	Depends. If your lite is air cooled it can be closer. If you have a fan between the canopy and lite it will help. I have an air cooled 400W with a fan between it and the canopy and I keep it about 10-12 inches from the top with no problems. As always, use the back of your hand as a guide.

07-10-2010, 09:55 AM	#3 (permalink)
lynamfamily4 YaHookan Join Date: Oct 2009 Posts: 59 Thanks: 47 Thanked 5 Times in 5 Posts	ok thanks and yes i think i may be air cooled i know the ballast is built in it? but i will have fan between. do you think i should also have another fan on the plants them selves??

07-10-2010, 02:27 PM	#5 (permalink)
stoneric bougeman Join Date: Aug 2004 Posts: 5,646 Thanks: 704 Thanked 1,512 Times in 1,067 Posts	If your ballast is built into your lite, it will be hot. Air cooled lites come with fittings on each end for ducting although they sell kits to add to conventional lites to make them air cooled. Your fan or fans should be situated between your light and plants canopy catching just enough of your canopy to keep a continuous fluttering of the top of the plant. You don't want it directly at the plant or to low, which might dry out your medium.

07-10-2010, 02:28 PM	#6 (permalink)
stoneric bougeman Join Date: Aug 2004 Posts: 5,646 Thanks: 704 Thanked 1,512 Times in 1,067 Posts	Damn, I'm a slow typer.

07-10-2010, 02:39 PM	#7 (permalink)
lynamfamily4 YaHookan Join Date: Oct 2009 Posts: 59 Thanks: 47 Thanked 5 Times in 5 Posts	i created a new thread with pics and details

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)