Flowki
Well-Known Member
I'm no expert but have learned through trial and error and a lot of reading of what others did or did not achieve.
Led is by all accounts more efficient, so you ''can'' use slightly less W for the same yield as HPS in the right circumstance. In a flat canopy I would expect Led to yield more than hps since W for W led is putting out more light and spreads it over the canopy. This basically increases quality of all the top buds and is one reason why it's important to fill the canopy in a flat dimension with led, due to the unit design.
Most people who grow with HPS either use closed hood or a flat canopy. I never understood this outside of heat issues. If you can use an open wing cheap hood and shape the canopy into a cylinder shape (following the contour of the bulb basically) then you can have more canopy in range. Essentially you go from a 4x4 to a 6x4, something like that. This could allow hps to still compete with Led W for W in weight. Not many do this since they are unaware or simply can not be bothered. It isn't easy to achieve in the confines of a tent, but is definitely worth giving a go at some point. Some people go the full way and use a vertical cage, utilising every possible W of hps.
I just think that led for a lot of people is more practical in the way we all commonly like to grow. I would suggest that led quality or terp production seems to be superior to hps but that could well have been my lack of ability with hps or the added intensity and even spread of led W for W of input.
What I also like more about Led (cob specifically) is that the heat is sent up into the roof, making canopy tempts easier to maintain at a higher intensity. Light bleaching/stress can become a serious problem if not careful, but heat stress is far less of a limiting factor in light heights. In other words you will likely see heat stress with hps as it radiates it onto the canopy, before you see light bleaching, giving you less room to play with. The size and power of hps bulbs also doesn't help in spreading out the heat and light more safely.
I really don't have a problem with hps, I'd use it again in a stadium style format.. but I can't see that happening since led is a lot more versatile (you can do the same stadium with led). It's very forgiving if a canopy gets away from you, to angle lights and change individual areas of intensity as to not make the rest of the canopy suffer for a few wayward tops. People who use high W single led units are giving themselves all the downsides of high W hps and very few of the upsides of using led. I don't understand that choice either unless it's purely for easier logistics. Not everybody is about max yield, since that will most certainly include a lot more work, it's very relative.
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