Though a topic widely discussed, I started a new thread because its hard to find the important stuff amidst a lot of reading. And that is, LED and HPS are both excellent, but the choice of light depends on what temperature you are growing in, more than the quality of the light.
As a rough guide, you use LED in summer, and HPS in winter. Or a combo of both. No point using an expensive LED if it's 10 degrees C in your tent. HPS heat is often regarded as a negative, but for me in winter it's generally a positive, something I want.
Recently at the shop I got talked into getting a modern white spectrum 500w LED for my 4x4 with the promise of higher yields and cheaper to run. So I'm keen, but I asked what about temperature, its winter (min 6C max 20C average) so will it give me enough heat ? Sure the shop guy told me, it should be good.
Well it wasn't. It just wouldn't heat up enough. I tried less ventilation time to save the temp, but the plants got air starved and suffered, drooping leaves and yellowing. I put a heater in there, but I cant see the point of all that wattage for heat, defeats the purpose of a low power LED, so may as well use a light.
So I'm back to my HPS (600 and 400W in a 4x4). But I'll use the big LED in the shoulder seasons for sure. I've grown combo LED cob / HPS for years and I like LED, it works, and apparently the new gen white light LED give excellent yield. The extra intensity they're getting these days is impressive.
But HPS heat ain't necessarily a bad thing. And they're so cheap these days with the LED competition. they're both good. So forget the technical analysis nerd stuff, its too complicated for stoners anyway
