Saying the bulb has a spectrum of 4100k and that this is not good for growing isn't quite accurate. This measure of light color assumes a continuous spectrum, and is designed to measure how the light looks to the human eye, not to a photosynthesizing plant. Any HID bulb does not release light on a continuous spectrum anyway, and giving it a color number is just an average of all the wavelengths of light it produces. The horticulture bulbs are a higher number because they release both the normal HPS spectrum, and also some blue light that helps with growth. And plants do need light at both ends of the spectrum.

So I'd get the HTG Supply bulb. Actually, I did use one already. It burnt out after a day, but they replaced it free of charge and the replacement has worked perfectly.
khronik Reviewed by khronik on . cheapo HPS Going to need a new HPS bulb and im kinda low on fundage. I did couple searches, but didn't find to much on using sylvania bulbs from Lows. I seen one there for 20 bux and thats right in my $$ range. I had decent dence buds with my old HPS bulb(bought the setup on craigslist) But I noticed my yield was sub-par compared to the one I did with 1 70 watt hps(brand new, non horti) and 6 cfls. I'd like to just get a new bulb for it, so I can rule that out as a problem. Can I get good yields Rating: 5