In general I agree with post #2. A MH gives the proper light spectrum for vegging and a HPS gives the proper light spectrum for flowering so for ease and cost saving a conversion bulb/light setup is the best way to go for most.
I also agree with the part about not using CFL’s. They work but not well unless you go into overkill. Many do not see it as being overkill but that is still what it is. If you total the amount of CFL’s used by those with truly successful CFL grows they spend as much as it costs to purchase and operate a 400-watt dual MH/HPS grow light. Anyone who used CFL’s and does not do that does not have a truly successful setup regardless of their personal opinion and what their ego forces them to claim.
When you compare grams per watts used no present form of lighting beats HID lighting and the combination of MH and HPS produced more grams per watts used than just using a MH or a HPS alone.
Ok, I will contradict myself somewhat but with a caveat included. LED lighting will out perform HID lighting but only IF someone can afford to purchase large numbers of high quality LED lights and IF they know how to properly position them. If they can do that they will end up with more grams per watts used but since presently LED lighting is beyond the reach of most cost-wise they are more or less not relevant much the same as someone who is looking for a quality automobile and has $30,000.00 to spend being told that a $300,000.00 model is higher quality. If they cannot afford it its level of quality does not matter in the least in decision making of their purchase.
I have vegged plants side by side using both a MH and a HPS and there is a difference. Using beans from the same pack, in other words the exact same strain from the exact same pack of beans, plants under a MH were tight and had very close nodes. The leaves/branches were stacked like playing cards and the exact same strain from the exact same pack of seeds vegged under a HPS the leaves/branches/nodes were spread out a good bit farther.
Proper lighting has been figured out for some time now. It is not as if lighting is in an experimental stage were there are unknowns. Certain things have been proved to work and to work best. HID grow lighting is one of them.
If someone were to look at the setups of the overwhelming majority of those using CFL’s they would find that they are made up of a collection of CFL bulbs that were designed for home lighting. Yes they still put off light spectrums that plants use and can grow under but still that was not their intended design or use.
What most CFL users have is a penny ante nickel and dime beer budget Rub Goldberg setup slapped together using various components from home improvement stores like Lowes and Home Depot and discount stores like WalMart and KMart.
Very, very seldom do you see people with CFL setups using actual CFL grow lights designed to be grow lights and intended to be grow lights that incorporate high quality reflective hoods.
If CFL’s are so wonderful why do people take the Rub Goldberg route? Because they cannot afford high quality lighting regardless of it being HID or CFL. If they could they would buy actual CFL grow lights with high quality reflective hoods instead of slapping together a collection of home lighting in a Rub Goldberg setup.
Now saying that steps on a lot of people’s toes and has caused a number of harsh replies on this site and also on several other sites but it is a fact as much as time and tides. People have egos and they want and need to believe they have a fantastic setup that is state of the art and they do not want to accept that they have a Mickey Mouse setup so they fervently argue that they have the best of the best when they in fact do not.
I have given the example before picking at random a 315-watt CFL grow light with an average quality reflective hood. The purchase price before shipping is $199.99. For $164.95 before shipping you can purchase a 400-watt HID grow light that is a dual MH/HPS setup with a reflective hood that is equally as good or better. For $35.04 less you can have a dual MH/HPS grow light with 85 more watts and it will cover a larger area and give better deeper light penetration.
But because it costs more to get less using real true CFL grow lights people who cannot afford higher quality lighting take the Rub Goldberg route and those that can afford higher quality lighting purchase HID lighting. Some people who purchase HID lighting make the mistake of going strictly MH or HPS, again mainly due to cost but in some cases because they are ill-informed. Like the Rub Goldberg CFL users will normally they will claim their setup is spot on due to not wanting to accept that they do not have all that can be had when they want and need to believe their setup is a hand rubbed Stradivarius.
In both cases they tend to mislead newbies by advising them to follow in their footsteps and duplicate their errors. The more people that copy them the more their choices are validated. Again the ego factor at play.
Misinformation is in an overabundance on sites like this and ill-informed beliefs and personal opinion tend to rule the day far too often. It is seen in anything and everything from grow room design/setup/equipment to strain choices to germinating techniques to care and feeding of plants to topping and in trimming fan leaves and when to harvest and how to dry and cure and store your harvest.
Advice that contains wording like ‘this is what I do’ or ‘this is what I believe’ or ‘this works for me’ etc. is normally the worst information for someone to follow because it is normally based on personal opinions passed from one grower to another instead of being based in fact.
As much as I love sites like this most people would be far better off using Google and researching on their own and or purchasing several well written how to grow books than they ever will be relying on the ‘this is what I do’ or ‘this is what I believe’ or ‘this works for me’ information found most often on sites like this.
