Can you elaborate on lighting and how much a plant needs? Asking as I too have a 150w HPS, in a cab, the usable space inside is about 33x29x14 inches. I almost bought the 250watt, but figured it would do nothing but waste space and build up more heat in my small cab.
I've also got two to three 23 watt CFLs running(2700K), which I added just to try and get in the small spaces for the side, or places where the HPS might not penetrate to due to foilage.
the 150watter puts out 16K lumens, which is well over the 10K you'd want. So are the CFLs I have added doing anything other than generating heat? Woudl I be better off putting in a 6500K CFL if I am going to use it?
The 10K lumens is per square foot... So since I have less than a foot and a half, and 16,000 lumens, it works out to a bit over 9100 lumens inside my tent. So to figure out lumens you need to figure out the square footage of your grow space (in this case 33" by 29"). That is a huge difference from the size that I am running, so in your specific case the 250 watt would have been a good idea. Again, best number to shoot for is 10,000 lumens per square foot.
As per your sidelights... Think about it this way... A 23 watt CFL puts out about 1600 lumens. So even if you were to have those lights a centimeter away from the plant itself, it would get at maximum 1600 lumens, still less than 20 percent of what it would need for flower. So to decide whether or not those lights are actually doing anything, you would have to figure out how much light those areas are getting from the fallout of the 150 watt hps. I'm sure the CFLs are helping, but considering their super-low intensity, I doubt they are helping that much. It might be better to get a single, bigger and brighter bulb in there... Like a 40 watt CFL (closer to 3000 lumens). So if it came down to switching to a single larger bulb, vs running smaller lights, I'd always go with the bigger and brighter bulb. Light intensity is the most important thing for flower.
Your grow space is significantly larger than mine, so I'd go ahead and leave the CFLs in there for now since the 150 watt HPS isn't going to give you enough lumens (or rather, the "ideal" amount of light... it'll work fine). Remember, however, lumens don't add. So five bulbs at a 100 lumens does not equal the output of one single 500 lumen bulb. More bulbs just spread the light further. This is why I would go with a single bright bulb, over many less bright bulbs. So I'd get rid of those 2-3 CFLS (23 watters), and get like a single 40-55 watt CFL in there.
As for color spectrum, that does add... I leave a CFL (6500 Kelvin) in the tent during the stretch phase of flower, not for the extra lumens but for the extra blue light. I'm actually thinking about leaving it in there the whole time this next grow so see if the bluer light will give me denser buds. I figure if I add 20 percent 6500k light, it should be a good place to start. So since I have 16,000 Lumens from the HPS, I'll grab a CFL that puts out around 3000 lumens (I think a 40 watter would be good enough).
