ok i know the floros use less energy and all then the hps, but in the end which one is the best system? like i want to grow somewhere around 5 plants that could probably be done easily with a 400w hps, right? but how many 4 foot floro tubes would it take to grow this many successfully? also i have read that the plants hardly consume any of the light that an hps system puts out, is this true? if it is then why does anyone even use this method of lighting? does a plant absorb more light from a floro? thanks for any help...
don't know bout the technical details but common sense to me says that you should use the stronger light source (hps) because you can have a single light and simpler installation than banks of a fluro if they are weaker. I have a 400W HPS but still haven't got my grow in order using it but am itchin to. I have coated my cab with 4 coats of gleaming acrylic white as much as I've done. it was always my intention to grow about 4 which would fit in the space. originally had 2 hps like the one I have now and gave the other one away to a friend who set up straight away at his and the babies just raced out of the pot, and he had the light well up I think too high from the plants, hadn't coated the cab very well just one quick coat of flat white and basically his setup was very roughshod. but they took off and kep going. the closet was flooded with light and I had to put the sunnies on every time I peeked. btw don't give your lights away like I did I was supposed to get a share of the grow but never received anything, but he was a bit of a selfish hippy when it came to the stash. talked it up tho. I was wondering about leaving an mh or hps on 24 hours, wouldn't it be better to leave any light on for 18/6 rather than 24/0 because the light needs to have a rest and cool down just like anything.
the fluoros dont have the "penetration" the hps has. an hps looses less light at greater distances. but that many fluoros the light is coming from a wider source area and there will be less shadowed area, but still the lower branches might not be getting the best from them. fluoros are best effective up to about a foot away from them, so are better for shorter plants. if you possition the tubes all around the plants so the lower branches get light too, this might solve the problem. watt for watt though, i'd still reccomend the hps to get more bud per watt, i speculate. also of great importance to consider is the spectrum of the fluoros. not all fluoros are the same. and you should really do your research to know you're giving the plants the best colour possable. but to keep it simple, reds for your buds (thats what you want) and blues for more veg growth. some people reccomend a mix, but usually go for mainly reds. there are "full spectrum" bulbs also, but still these vary alot. some call themselves "daylight" but i think these tend to lean toward the blues. there are also bulbs specially designed to more accurately mimic the spectrum given off by sunlight, used for treating s.a.d. and even one of these in an array would be very good for your plants. but still... hps, its the shit. a well kitted out room with fluoros, that has maximum reflectivity of the walls and all surfaces will surpass a poorly kitted out room with an hps and brown walls. however, if you have the money for the initial outlay, and the patience and time to both build and research what you're doing, go for LED arrays. LED has on paper, all the figures to beat HPS, it's cheaper in the long run (bulb replacement gets expensive) and can be formulated to give only the exact peaks in the spectrum directly responsable for triggering growth an flowering. but you've got to know what you're doing, and will probably want to "pulse" your lights for even more efficiency. also, most people growing with LED also add a little fluoro for the blue as the blue LEDs are more expensive, and less required for your purposes.
If you go with flourecent, try the compact ones that fit into a regular light socket. You can get more light per square foot than with the four foot jobs. This setup is preferable for your vegitative room, but the HPS has red in the spectrum, like the sun low on the horizon in fall, so they are better for flowering.