Lighting question???

[rb2006]

I ant useing a 400w HPS and would like to know about how far away i should keep the light. :cool:

[Firepower]

If the the temps are good and you have good air circulation, you should be able to keep them 16-18 inches with no problem, rule of thumb, but your hand over the girls for a minute, if you feel it too hot, then it is too hot for them.. good luck.. :aok:

[thc is good for me]

Hey this chart is very helpfull


Its got all that crap on the side because i posted it a long time ago and it the site wont let me re-post the original sorry for bending the rules :banana:

[Hick]

Hey this chart is very helpfull


Its got all that crap on the side because i posted it a long time ago and it the site wont let me re-post the original sorry for bending the rules :banana:
those charts were a part of this site long before you were a member thc'.. ;)
here is the link to the sticky that has those "distance charts" in it...
http://www.marijuanapassion.com/forum/showthread.php?t=19360

..more specifically http://www.marijuanapassion.com/forum/showpost.php?p=30718&postcount=4

[papabeach1]

that is just what we needs!! for perfect measures on the light to plants sweet!! just put some plants under the 600 hps I do see differences

[rb2006]

Hey thanks alot guys this is the only forum i can get any answers on i think i will stick with this one for all of my grows. Great forum with great people thanks tons.

[thc is good for me]

those charts were a part of this site long before you were a member thc'.. ;)
here is the link to the sticky that has those "distance charts" in it...
http://www.marijuanapassion.com/forum/showthread.php?t=19360

..more specifically http://www.marijuanapassion.com/forum/showpost.php?p=30718&postcount=4

I would have sent him to where to find the picture but i didnt remember where i saw it. I wasnt trying to take credit for the chart i just remember someone posted a pic of the light chart for me and it was really helpfull.

[Tater]

Thats a good chart to use as a reference but its rating for what is to close to the bulb is nothing more than personal opinion. If you can cool the bulb enough you could have your plants two inches from the bulb. Heck if it was cool enough the leaves could touch the bulb. The problem is HID bulbs put out a lot of heat so now burning the plant becomes a problem. The answer to your question to me would be, as close as you can without burning your plants. Just to illustrate this look at the difference between 4 and 6 inch's from the plant. At 4 inch's the plant is receiving 143239 foot candles of light from your 400watt HPS. At 6 inch's it is receiving 63662 foot candles of light. So just that two inch's diminishes the lights effectiveness by more than 44 percent:eek: That is a HUGE difference. The closer the better. Cool the light with a fan, or better an air cooled hood, or better water cooling.

Good luck with your grow keep us posted.

[Rambler]

you should read this post its about fluorecent lighting but it has a little about hps and the amount of light your plants get when you have the hps too high over them. http://www.marijuanapassion.com/forum/showthread.php?t=8581

imo it should be a sticky in the lights threads it helped me lot.

[BuddyLuv]

Hey thanks alot guys this is the only forum i can get any answers on i think i will stick with this one for all of my grows. Great forum with great people thanks tons.

That is what I love about this site as well. I was very disappointed in some of the others, flaming and what not for asking questions I could not find by searching. I have learned a lot the short time I have been here and my plants are going to reward me for using this site and help of these members.

[rb2006]

I never expected this many replys!!!! oh and im am very sorry i didnt put up any pics. i guess i will have to do that. Thanks again for being so helpfull!

[Rambler]

nice pics, how old are they now?

[rb2006]

thanks man. they are about a month and a half.

[andy52]

wow,hate to butt in here.but i keep my 400w HPS almost touching my plants.i can lay my hand on the glass on the reflector and not warm at all.is this wrong???thanks guys


my cable modem was down for some odd reason all day yesterday.was back workin this morn. any ideas guys?/thanks

[Tater]

The answer to your question is in this thread seek and ye shall find.

[thc is good for me]

Rb2006 Great job on those plants they look great!

[rb2006]

5 days into flowering hopeing for ladies!! :holysheep:

[puffnstuff]

It doesn't matter how much air you have flowing over your bulb, it will still put out all of it's radiant heat. The air only cools the item's(metal and glass in the hood) that have been heated by the radiant heat. the air cool's by impacting on these heated surfaces and remove's it through conductivity. This is why it is so important to have a fan blowing in your grow. It is to remove the heat from the plants through conductivity by impacting on the surface's. You can greatly increase the cooling effect of your airflow in your hood by causing the air to be disturbed instead of flowing straight through. The turbulance inside the hood will cause more air to impact on the interior surface of the hood and remove the heat.
puff