Just got my 400 watt light

Installed the HPS 54000 lumen bulb set at 100%. Is this far enough away from the plant? I'm really stoked about this, but my ceiling was only made of drywall I found out. So I need to come up with another way to hoist the thing from the top so I bolted a side into the wall for now

Very first time growing with a light setup like this

Oh, and BTW who ever said this thing gets hot as f***... kudos to you man lol i was sweating just looking at my plant

keep the light far enough away from the plant so it wont burn or gets too warm, use your hand to judge distance, too hot for your hand, too hot for the plant

When I put my hand on the plant it feels 'cool' About 6 inches up, 'warm' then gets hotter from there

You better get some fan action going there, because that light needs to be WAYYYYY closer to your plant than that. Like within 12-16 inches to maximum your lumens...at your current distance you aren't doing squat for that plant.

I moved it down about 6 inches. Its at about 14-16 inches away now, I also have a fan in there

Urfacemypalm said:

I moved it down about 6 inches. Its at about 14-16 inches away now, I also have a fan in there

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Have a fan blowing at the top of your lady and the area in between your lady and the HPS bulb. Doing this, you might be able to hang the light even closer than where you have it now...
Do you have an exaust set up at all?

With a fan blowing right under the hood across the glass and above the plants.
you should be able to get the light within 10-12 inches of your plant.

Not an exhaust. I leave the door open in the daytime. Night cycle I'll have any clones under cfls for vegging in another area. But when this is on in the daytime I'll just move the clones there.

Heres a pic of my adjusted setup. I have the fan blowing on low, but it blows the plant around a bit, is this okay even in flowering?

Dogenzengi said:

With a fan blowing right under the hood across the glass and above the plants.
you should be able to get the light within 10-12 inches of your plant.

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Boy am I glad I saw this on my feed...lol...I was going to ask the EXACT same question!! My 400 HPS is scheduled for delivery tomorrow...I don't have my exhaust fan yet and my new cabinet is still being "renovated"...my plants are cramped up under too few CFL's and I want to hang my HPS while I finish the new cabinet!!
If it seems to much for them I can just dim my light?

Yes you can just dim, remember the hand test.

I find a cheap digital thermometer from lowes very Handy to know what temps are.

I have a temp and hygrometer but the temp varies by how much direct light it gets.
The plastic seems to absorb heat and hold it.

With the heat gun I can read the temp of the plant in different locations as well as other things in the tent.

Point a fan so it blows the air warmed by the light away from the top of the plant.

Start with about 14" of space if you see no burn go down two inches and continue till you see any negative signs then back the light off.
I have a 10" fan blowing between my plants and I have some tops as close as 9".

I keep a ruler and level by my tent but I am Nutz

If you went for a cool tube and Fan you could have that light 9-10 inches away.
Do you have fresh air being blown into closet?

Air movement is paramount.

Its good to have a fan blow on your plant, it strengthens the plants stems.

Air movement will also speed your soil in drying, but you need fresh air coming in and a fan were you are using it now too.

Urfacemypalm said:

Heres a pic of my adjusted setup. I have the fan blowing on low, but it blows the plant around a bit, is this okay even in flowering? View attachment 2851645

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You really only want the fan to just slightly move the plant a little bit. Not only does it move the air around, it signals the plant to grow sturdier branches ( it doesnt want to get blown down ! ) Anyways, you dont need much air movement. I use 2 400 watt lights much like yours and one of mine is covered in glass and the other is open like yours. I use an oscillating fan and I even use a timer so it shuts off for awhile then it comes on again. Good luck, you'll notice a big difference with this light compared to CFL. Its night and day.

You can get that light closer than that. I have a 400w sunsystem 2 and its about 11 inches from the top of my plant, I also have an oscillating fan blowing on my plant as well.

Yea the fan moves the plant a little now, it's perfect too. Can't wait to see the final outcome of this, have two other clones under the cfl's now too and more on the way if I need them

I keep my 400 5 to 6 inches away at most. but I have an air cooled hood. any further it feels like a waste because they don't penetrate deep to begin with. I only use mine for veg. then I bump it up to the big boy.

I'll prolly rig a cool tube to it at some point but for now its a huge step up from the cfls I was using and hopefully I get an oz or two MAYBE offa this bath, and maybe more off the two other clones I'm raising.

im running a 400 watt myself, for my small plants i keep the light about 18 in away, but if you can keep it cool you can get it closer, just watch out for light burn.

You don't need a fan for a 400w HPS, particularly in that setup as the fan is just going to spread odor all over your living area. Some strains can tolerate being close to the light, some not. I generally find being closer than about 18" can cause foxtailing on the tops.

EDIT: Fan or not, the closet door must be cracked open a bit to dissipate heat.

Its set at 15.5 inches away. Venting is in the daytime. Its my flowering room. So closet door is closed to presrrve darkness at night left open to vent in the day. Not worried about odor n all that.