dresser grow use a 400w cmh or 2x 250w cmh's

[sleepyhead]

so i got alot of wood and nothing not really sure on size yet because i havent decided on lighting i was thinking of using eather 2- 250w cmh's or 1 400w cmh but i would like to plan to pack a second 400w in 3 months. i will be air cooling the light(s) should i do it vertical instead never done that before i dont have alot of space but i heard from some it yields more

i plan on making this a dedicated flower cab not sure on demensions at this very second, i wanted to figure that out after i got an idea but the question i have is are 2x 250watt ceramic metal halides going to produce a bigger yield than 1 400w ceramic metal halide ?

this is where i found the bulbs http://advancedtechlighting.com/cdmed18.htm

starting
Lumens
250w- 20,500

400w - 34,800

mean of lumens

250w - 16,400

400w - 29,600

so i got the idea starting with 1 400w instead of 2 250's would make for more growth? would it not

 

[been]

I'd go with 2 250s but if your lung room or whatever can handle 800 watts get the 400 now and upgrade soon.

 

[4u2sm0ke]

I too would go with the 2 @250 not sure about vertical lighting in a small area..Your heat is gonna be the bigest factor here IMO...even with it beeing cooled..I wish ya the best louck..cant wait to see this in action..take care and be safe

:passingjoint:

 

[convex]

The 250's and scrog it to get them close.

 

[sleepyhead]

ya i cant wait to post this box growing something

250w bulbs ordered. passed on the 400w cmh ! eek
i do feel weird getting a smaller bulb but theres going to be 2 so im going to hope it will be the same kind of yield as a 400w and im going to try and scrog it. i really wonder what kind of yield i can get of this OH this is going to be fun micro grows woot!

 

[0sWizZle]

you should have stuck with a plain HPS bulb....your yield would have been 3-4 times bigger

 

[sleepyhead]

not 3-4 times more maybe at most 1/6th better yield with hps lamps but ive noticed using uvb lights with hps lamps adds a decent amount of extra resin weight maybe its not true but from what im seeing looks like indoor with the power of outdoor with that extra resin that outdoor gets but of course a lower leaf ratio

some people aint worried about yield as much.. only stess getting under a certain gram per watt equation but hopefully working hard to make a power bill worth while in the end

 

[sleepyhead]

oh a friend of mine is doing a 250 watt cmh grow and that will be setup before mine :D its going to be awesome to compare the finished buds

 

[Bill Lermer]

Two of the 250w CMH would likely do better than a single 400w CMH. Because the two bulbs would produce two different angles of light (resulting in fewer shadows on the leaf surfaces); and the total lumens are greater.

You might consider the new generation of CMH lights, GE has them in 70 watt.
This "Ultra" version of the GE CMH has more efficiency and a better spectrum
(91+ CRI). You could run four of these in a small area, with more angles of light
and fewer shadows.

Two of the 400w CMH, with proper reflector, can cover a 2.5' x 5' area.
About 15 plants.

 

[ookiimata]

Great thread. I'm debating the same question, only with HPS instead of CMH (never used those before, too scared to try). I assume two bulbs is always better than one, so it's good to hear that confirmed. My question is whether the two 250 bulbs will put out more heat than a single 400w? Ballasts will be outside the cab, so I'm only dealing with the actual bulb heat. Anyone have experience with that or care to make an educated guess?