400W HPS enough for 5 plants??

Hey there, up until last night i had my heart set on using CFL's to grow, but then i found out that i would need loads of CFL's to grow my 5 PPP plants, so i decided to go with HPS.

Now i was wondering if 1 400w HPS light would be enough light to grow 5 PPP plants, i will be using the 400w for both the veg and flowering, also how long is a 400w HPS light (i mean in terms of length)

Any and all help is appriecated

You can definitely grow 5 plants

the BULB isn't that big at all. 5-6 inches.

How big a reflector you have is up to you.

the bulb is about 11" and it should cover a 3x3 area no problem ...good luck

hi if u gonna use hps all the way expect very tall plants. in veg they will keep streching up towards the light 4 that little bit of blue spec thats in hps. and u wont be able to get it very close to the tops coz they will burn easy.if u gonna spend out on a 400 light u might as well buy a metal halide bulb for the first 4 weeks .mh is the blue spec they need and love .they tend to grow alot shorter fater and wider with this bulb.

I hope so, since I'm putting 35 plants under 2 of those.



that's in millimeters, so about 29 cm, which is roughly 11.5 inches.


5-6 inches!...that must be one of those new compact 400W HID lights. lol
you must be thinking about your dong! ROFL

i have the same setup and my plants are growing great.

spliffy777 said:

hi if u gonna use hps all the way expect very tall plants. in veg they will keep streching up towards the light 4 that little bit of blue spec thats in hps. and u wont be able to get it very close to the tops coz they will burn easy.if u gonna spend out on a 400 light u might as well buy a metal halide bulb for the first 4 weeks .mh is the blue spec they need and love .they tend to grow alot shorter fater and wider with this bulb.

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Or you can just place vertically four or six 4200k or higher flourescents arund your plants to give them a light blue sprectrum, But HPS should be fine nomatter the situation unless you have a problem with temperatures being too high.

thanks guys, you answered all my worries
i might just get a few CFL's to compliment the HPS during veg
*EDIT*
i just found out that the ballast im getting can also run MH so i will most probably buy a 400w MH bulb for the veg

DRGreyMind said:

thanks guys, you answered all my worries
i might just get a few CFL's to compliment the HPS during veg
*EDIT*
i just found out that the ballast im getting can also run MH so i will most probably buy a 400w MH bulb for the veg

Click to expand...

there you go. a switchable ballast would be great. i have seperate ballasts so its more work switching them around.

Im trying to grow six plants under one hm light and 1 hps light.
If they are both 200 watts will that be enough?

rule of thumb is the more light the more yield, 6 plants under a 200w might be pushing it a bit

youngmangrowing said:

Im trying to grow six plants under one hm light and 1 hps light.
If they are both 200 watts will that be enough?

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you should do alright using both those 200 watters. just try and get them as close to the plants as you can and still keep it a safe distance.

I was told that you are supposed to have 75w per plant minimum, if you use that as a guide you can't go wrong! good luck.

DrGreenThumb said:

I was told that you are supposed to have 75w per plant minimum, if you use that as a guide you can't go wrong! good luck.

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that may be so, however, if I used a 75w incandescent bulb, that would be inadequate.
it's better to go by lumens and color temperature.
like a minimum of 2000lm per sq ft. more lumens per sq ft is a very good thing.
high temp, over 4500k, for veg.
low temp, under 3000k, for flower.
however, weed will grow, in any temperature range.

I have four bulbs, some slightly different, others very different. range from 26500lm to 47500lm, 2100k to 6500k. MH and 1 HPS, 400w, 1 HPS, 360w. I set them two at a time, in three stages. stage 1; both MH, stage 2; the more powerful, MH and HPS(360w), stage 3; both HPS. stage one averages 6500lm per sq ft, stage two; 8833lm psf, stage three; 7833lm psf.
I have 26 plants in 9ft squared. if done right, LST or whatever you choose...thats a lot of light for a sq ft!
if I went by 75w per plant, I'd only have 10-11 plants. also, I'd need, for my plants, about 50x40w cfls or 10x200w flouros, etc, etc...which kinda seems rediculous.

the thing is, that a 75w bulb, all bulbs for that matter, made by different manufacturers, etc, have different properties.
go for the lumens and color.
you'll, probably, be fine, but I don't know a thing about your lights except the wattage...