vegging 400w hps fan cooled or 250w cfl ?

If your growin 1 or 2 the 250w will be fine for veg then use the 400w for flower... If your growin more then that id use the 400w you get way better light penitration... If power consumption isn't an issue id go ahead and use the 400w hps from start to finish especially since it's duel spectrum.

 

Yeah man you'll do way better with the HPS with that many plants... The problem with cfl's is they have to be extremly close which limits how many plants you can put under them... You'll be able to cover 3x3 foot with the hps.

 

over 3 plants...definately the 400 hps. just watch them for stretching and u will be happy with the results

 

When I first moved to Australia, and suggested that I'd been using a series of 400watt HPS lights to grow, they asked jokingly, "what, to germinate your seeds?"... not saying they don't work, especially for the veg stage and even flowering, they absolutely DO! I still use a 430watt HPS for vegging now myself. But just to give you an idea of the kind of power and lumen-output you're dealing with...


This may help as a guideline;

150w incandescent = 2,550 lumens or only 17 lumens per watt

150w halogen = 3000 lumens or 20 lumens per watt

150w of Fluorescents = 9,000 lumens or 60 lumens per watt

150w of Compact Fluorescents = 10,500 lumens or 70 lumens per watt

150w Metal Halide = 13,500 lumens or 90 lumens per watt

150w High Pressure Sodium = 16,000 lumens or 107 lumens per watt


So, 250 watts of CFL = only 17,500 lumens

While 400 watts HPS = 42,800... in other words, using less than twice the power, it produces nearly two and a half times the lumen/output.


You'll have much faster and hardier growth using the 400watt HPS all the way through both veg and bloom.


So if time is an issue, and you want a faster growth period with larger plants as an end-result, you'll want the higher wattage and lumen output, but if temps are a larger issue for the moment, than time, then go with the CFLs.