CFL vs HPS

Hi all,

I had previously decided to go with CFL's for my small grow box in my shed. The space is 32inch wide by 18 inch deep by 4ft tall. I was going to use 4 105W CFL's with 2 being 2700k and 2 being 6400k as I am looking to do an autoflowering strain in soil. I am only looking to have 3 plants flowering at a time and doing a standard grow to begin with.

I have now realised that I can buy 1 400W HPS Dual Spectrum light with ballast and reflector for the same price as the CFL's.

I'd like to know what would be the best purchase for my space and the grow I am hoping to try?

the heat from the hps will cook your plants b4 they can cook you, depending on your ventilation. in tight spots cfl's are the best. in terms of light penetration hps owns. in your spot, i'd go with cfl's and keep em right on top of your plants. cfl's do give off heat so a small pc fan can keep the cfl's cool enough to keep the heat in check.

iampolluted said:

the heat from the hps will cook your plants b4 they can cook you, depending on your ventilation. in tight spots cfl's are the best. in terms of light penetration hps owns. in your spot, i'd go with cfl's and keep em right on top of your plants. cfl's do give off heat so a small pc fan can keep the cfl's cool enough to keep the heat in check.

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Hey,

Yeah i was worrying about the heat factor actually. I intend to have 2 120mm PC fans exhaust and 2 120mm intake with a total of about 110CFM for the exhaust and 110 CFM for the intake. I guess this is not going to be enough for the HPS light?

Yeah the 400W HPS will cook them however in a space of that size however you could get away with a 70w HPS or possible 150w HPS (security lighting) but you will still need good ventilation, but if you choose CFLs I would surgest a either a 125w/150w ENVIROGROW/ENVIROLITE bulb as they are much much better than household CFLs but ventalation is still required. 2 Small cpu/simerlar fans attached to a transformer plug + wired together, one at the bottom sucking air in and and one one at the very top blowing air out ...... JOB DONE! hope this helps - STELTHY

stelthy said:

Yeah the 400W HPS will cook them however in a space of that size however you could get away with a 70w HPS or possible 150w HPS (security lighting) but you will still need good ventilation, but if you choose CFLs I would surgest a either a 125w/150w ENVIROGROW/ENVIROLITE bulb as they are much much better than household CFLs but ventalation is still required. 2 Small cpu/simerlar fans attached to a transformer plug + wired together, one at the bottom sucking air in and and one one at the very top blowing air out ...... JOB DONE! hope this helps - STELTHY

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Thanks Stelthy,

I was looking at getting 4 x 105W CFL's so having a total of 420W from them. Is this overkill for 3 plants? As I said in OP I was looking at doing Autoflowering ad so was going to have a mix of spectrums.

you could do this with just 1 of the exhaust fans running through a home made cool tube (hurricane lamp glass) holding the hps. go with a passive intake and put a decent fan in there to circulate the air around the plants....depending on the temps outside the box, it shouldn't be more than 80-85 degrees inside it.

i started small for vegg so maybe cfls for now for vegg and use the HPS later for bloom. i purchased a T5 4" 6 bulb red/blue mix for my vegg room to start them i'll add a second 4" 6 bulb later when the rest of the plants come around and than ill take a couple out every two weeks and stick them i a second booth for bloom under a HPS so i'd say start small for what u need now to get them going and get the HPS later, also ive read it's good to vegg under a metal halide and than bloom under HPS