800w (2 x 400w) bare bulb help!

[mrtibbs316]

I am going to be growing with 2 stacked 400w HPs bulbs in a 4 x 4 tent.

I am going to make a circular vertical scrog, but I have now idea what the distance from the plants should be.

These are bare bulbs, with no cool tubes, and a fan blowing up underneath.

Any suggestions?


I just want to know what distance you think I would keep from the lights.

If you answer please make sure you put if you are stating the diameter or radius, and also unit used (cm, inches etc)

Thanks for the help in advance. I appreciate all the help this forum has given me

 

[mrtibbs316]

Anyone out there?

 

[pilsung]

with only a 4 x 4 footprint there's not much choice of where you position plants, you'll want to keep 'em tied and trained so they stay more than a foot from the bulbs. i would cut pieces of wire fencing to install against the tents walls and tie girls back in a rear scrog.

i don't currently use tents but advise i was given by a master grower is to have an active intake fan so the tent is kept at a positive pressure. bowing the walls out. and to use multiple fans to have a real windstorm going on. carbon filter at the highest point and a carbon filter out side the tent if smells are a safety concern.

 

[sdf]

You should consider using a cmh bulb, the philips 315w agro elite cmh has been documented pulling 17oz off one in a reflector. With two done VERTICALLY BARE BULB could bring in a lot of flower.

Also because of the spectrum it will run cooler, I've heard of people able to have the plants as close as 6 inches without burn but I'd stick with 8 inch radius from bulbs

 

[ttystikk]

@sdf has a great idea, 315W LEC lights are very efficient and produce a MUCH better spectrum than HPS.

 

[sdf]

My next grow will be with the 315 cmh, if you want quality over quantity I believe that bulb would hit the mark without negating weight. If you use a heavy sativa like sannie's Jack herer you could bring in over a pound of grade A bud with 2 lights, maybe even 2lbs if your good enough

 

[ttystikk]

My next grow will be with the 315 cmh, if you want quality over quantity I believe that bulb would hit the mark without negating weight. If you use a heavy sativa like sannie's Jack herer you could bring in over a pound of grade A bud with 2 lights, maybe even 2lbs if your good enough

I'm currently running an earlier version of this technology. 860W CDM lamps are similar, though not quite as efficient.

 

[sdf]

Are you running the earlier 400w cmh from philips? And yea I heard the 860w isn't as efficient as well as produces more heat.

 

[ttystikk]

Are you running the earlier 400w cmh from philips? And yea I heard the 860w isn't as efficient as well as produces more heat.

I'm running the Philips 860W CDM lamp. It produces proportionately more heat for its output rating, but far less than HPS.

It works very well in my setup. It produces a lot of light with a great spectrum curve, works in the vertical position, it's BARE BULB RATED for safety and they're supposed to last a long time.

By contrast, I'm having trouble getting enough of the little 315W lamps in one place to do much good!

When I got into this, the hydro stores told me to veg under MH and bloom under HPS. I'm doing the exact opposite and the results speak for themselves. I wonder what other advice given out on faith at hydro stores is equally suspect?

 

[grapefruitmarmalade]

You guys know anything about CDO-TT bulbs from Philips?

 

[Rev.thenatural]

Two stacked 400 14000k Hamilton beach aquarium hid, is what I use for flower. Run your trees at least 18 inches away and then every day, give pots a quarter of a turn. Most run lights to close and then don't stretch properly for veg or bush nicely for flower. Gave suggestions a few threads down that you may consider. Proper stretching in veg and defoliation done right, is what's needed for maximum yield, hid if you want quality and ripen the cannabinoids that are the true healers. HP's, is not for cannabis..period..none of them. You get dialed in and learn this, you will knock down pounds a tree with your setup..promise. Get a couple conversion bulbs, cheapest hid will give you better bud. Go with a couple standard Phillips or ge or sylvania so not to spend more money than needed. Hortilux sucks so never waste your time their. Learn proper organic soil building and compost tea and have a blast healing yourself and others. One love, rev.thenatural

 

[harris hawk]

Seems like a lot of "light" for a small area - saying that - just make sure your air circulation is good - yous will also learn that plant movement is important so plants can caught that light, if you don't do that - you will have plants that have a "weak" side; therefore reduces yields. CFL's for vegation and HP's for flower (2400K = flower and 5000K for veg)

 

[brimck325]

I would set the screening about 18-22" from center. You will be surprised how close you can get em with out burning, if set up right.

 

[ttystikk]

Weak side, lol. Other plants do too, it's called the 'underside', lol

Anyway, train your plants to cover the trellis on the inside, put a fan at the bottom blowing upwards to help heat escape and happy growing!

 

[zep_lover]

i run 4 x4 x6 cabinets with 2 600 stacked.i tie 1 plant to each wall.i trim the plant to one layer and try to make a menorah shape of the plant.i have one cabinet with a 6 inch fan and filter combo and 2 cabinets with 8 inch fan and filter.properly shAping and trimming the plant is very important.if you do not ,you end up with alot of larf.be sure to run the small fan blowing up on slowest setting.higher settings actually heat up the grow space due to the exhaust fan not being able to remove it as it is blown up at too high a rate. using 2 400 watters gives you exactly 50 watts per square foot in 4 X4 area.i have found running more plants just over crowds each other and hurts yield.