For those who use 400 watt hps lights

i have two plants, do they have to be exactly under the light or is the light powerful enough to give the required light to the plants.

i think it powerful enough for a 4x4, so as long as the plants are in that square footage then ur fine.

i think ill be alright it has a reflector on it i guess i could expand it tomorrow.i just transplanted my plants into buckets now there spaced out from each other then they were used to

im such a stoner sorry guys i bent the reflector a certain way now my whole closet is reciving excellent light

Yes 400w hps is more than enough for 2 plants

yeah you should have more than 2 plants under that 400w... always start out with around 10-20. that way you are more likely to have a few ladies.

i know but i am still learning from my mistakes check out my orange kush grow

i use a 400w hps in 2x2 grow area and only 2 plants, i could proberly get 4 or 5 in there.
4x4 space is just about the limit for 400w hps, you 16sqft 1 plant a sqft.

You could also just grow those 2 plants large or train them to cover a 4x4 area. Take advantage of the area your light covers. I like 400 watters because they run cool. Cooler than the higher wattages. Make a bonsi, lay a clone on its side and let the brantches flower up or lay down a screen for them to fill out.

edux10 said:

Take advantage of the area your light covers. I like 400 watters because they run cool. Cooler than the higher wattages.

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Same here,400 watters are the ticket,cheaper to add more later on & way more flexible as room & garden size grows.

a 400watters good for 3x3 so its easily good enough for 2 plants.peace

i just got a 400 watter, this is all great to hear

I would argue that 600w is the way to go, they have the best lumen per watt output out of HPS lights and run decently cool. plus they are almost the same price.

I'm using a 400 MH in a 5X5 space for veg.Right now there are 3 mothers and 36 clones in the space,without crowding, so youcan see the potential.When I first set up my room it was the only lamp I had and I could flower out 6 plants no problems.Good Luck with it.

400w hps, makes my cab hot

430 hps with Heavy exhaust, great circulation, and forced intake still makes my 4x4x7 hot

my closet is vented really well with the 400 watt i have like 4 fans going though.

Hidden Agenda said:

I would argue that 600w is the way to go, they have the best lumen per watt output out of HPS lights and run decently cool. plus they are almost the same price.

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Agreed on output vs cost but by going with larger lights like the 600 or 1000 you loose the flexibility that comes with the smaller 400,the larger the light the less flexible it is & the more drawbacks come with it.

Lets put the heat issue aside & talk about coverage. As im sure everybody knows light fades to the square of distance,the more floor area being covered the higher the light needs to be raised to cover that area,with raising the light you get alot of wasted lumens.

Ive found out that in my rooms using 2 400 watt systems vs a single 1,000 watt system the dual 400's outperform the bigger light in every way,i can cover a larger floor area & have the lights closer to the canopy,have more light directed where it needs to be & still have less heat over the single 1,000,plus by having dual 400's over the 1,000 if a ballast ever blows im not screwed,ive still got a light going in the room while i order a new ballast or repair the blown one.

The same would apply to running dual 600 watters,if you pit 3 400 watt systems against 2 600 watt systems you'll still have better coverage at the canopy & better light penetration to the lesser bud sites.

There are other issues that need to be considered also like line draw,on a standard 15 amp household line you can only run a single 1,000 watt system,on the same line you can run two 600 watt systems or three 400 watt systems.


Lumen ratings & costs to run are only a small portion of selecting lights,future room upgrades & even possible down sizing need to be considered when choosing lights,with larger lights its impossible to downsize in alot of cases,a 400 watt system will work many places where the larger 600 or 1,000 wont,IMO 400 watters are the most versitile & cost effective systems on the market.