Fluorescent Lighting

Discussion in 'Marijuana Growing Techniques' started by sillypuddy, May 6, 2007.

  1. sillypuddy

    sillypuddy Member

    hey, does anyone know if 6500 K fluorescent lights are any good? The ones people talk about all the time are the 2700 K and the 4100 K, but there are no 4100 K's in the country in which I am living.
  2. T.H. Cammo

    T.H. Cammo Member

    6500 k. flourescents will produce light in the "blue" range, so they will be fine for vegging. But flourescents (even the 2700 k.) are notorious for being weak in the flowering stage. You may want to think about some other light source for the flowering stage, like High Pressure Sodium. .
  3. sillypuddy

    sillypuddy Member

    are the fluorescents any better for flowering than incandescents?
  4. brainboy

    brainboy Member

    Yes, and TH I hate to disagree with you because I really respect your knowledge about growing but I've seen plenty of people flower fine with flourescents. Flourescents are better then incandescents at any stage, the key to getting good flowering with flourescents is to have some system so that the buds are all on an equal level so something along the lines of LST or SCROG
  5. T.H. Cammo

    T.H. Cammo Member

    Yeah, I know that flourescents will work! At least the newer varieties that are available since I stopped using them. But there's more to it than that - pro's and con's for each type of lighting system. People pick different types of lights for their own reasons, and may argue all day to rationalize why their choice is best. Some examples (based on an equal amount of square footage under lights):

    Pro's - cheaper to buy, may last longer (?), run a lot cooler (less ventilation problems), ideal choice for "micro-grows" or cloning/seedlings.
    Con's - more expensive to run, lack "penetrating power".

    Pro's - cheaper to run, good "penetrating power".
    Con's - higher initial cost and bulb replacement cost, heat control issues.

    Maybe I need a refresher course on "Lighing Economy", but as I recall Hid's put out quite a bit more light per Kilowatt than Flourescents. At the end of each month I am paying the bill, so I want the most efficient system - not just the cheapest system to buy. Maybe what I really need is a refresher course on "Leading Edge Lighting Technology"!
  6. sillypuddy

    sillypuddy Member

    so, if fluorescsents lack penetrating power, will I need extra lights pointed at lateral branch buds?
  7. T.H. Cammo

    T.H. Cammo Member

    Yeah! That's usually how they do it now with compact flouros (CFL's). Several of them at different angles, that allows the light to come from different points so that each light fills in the shadow left by the other lights. Kind of like a cross-fire!
  8. sillypuddy

    sillypuddy Member

    By the way, if I'm using a soilless medium, should I be fertilizing a lot more than with soil?
  9. M4N14C42O

    M4N14C42O Cannabis Connoisseur

    Hey T.H.!

    How goes it? Anywho, just not sure if i keep reading this wrong or what.....but aren't fluoro's cheaper to run than a HID?? Could be wrong, but anywho just a simple little thing i caught.
  10. M4N14C42O

    M4N14C42O Cannabis Connoisseur

    ^^^^unless your talking lumens per watt.....
  11. fishheadbob

    fishheadbob Member

    NO. #1 problem is always nutrient burn
  12. T.H. Cammo

    T.H. Cammo Member

    By M4N14C420:

    "...but aren't fluoro's cheaper to run than a HID??"

    My information may be a little out of date because the technology keeps changing so fast and I quit following new flourescent advances a while back (probably about time to update my research!). Anyway, yeah, it's basically about "lumens per watt". As I said earlier, flouros are probably the best choice for "micro grows", the reason being that smaller wattage HID's are not very efficient for some reason (maybe ballast losses?). The comparison is more notable in a "typical" sized grow space with, say, 400w of light.

    A 400w HID produces more "PAR" light (Photosynthetically Active Radiation) than 400w of flourescents, therefore it promotes more growth, therefor it is "cheaper" to run. Remember that lumens are "artificial" units of measure that just measure human visibility not "plant usability". Assuming that the only reason we are running our grow lights is to "grow", then the bottom line has to be how much yield vs. how much electricity was used. That is what I meant by "cheaper to run".
  13. T.H. Cammo

    T.H. Cammo Member

  14. sillypuddy

    sillypuddy Member

    Well, at the moment I've got 14,000 initial lumens (for two plants) from a bunch of 6500K CFL's, and I'm about to start flowering. The two plants I have under them are pure sativas (or pretty close), and they're 3 months old. The lights are all about 2 inches from the tips and branches. I know this is a lot less initial lumens than HID's, but I'm guessing I'm getting much higher % of those lumens reach the plant than from the HID's. If anyone is intereted, I can provide updates on how things turn out.
    BTW, can anyone tell me if I need to be fertilizing my soilles medium a lot more than I would with soil?
  15. T.H. Cammo

    T.H. Cammo Member

    By sillypuddy:

    "BTW, can anyone tell me if I need to be fertilizing my soilles medium a lot more than I would with soil?"

    Fishheadbob already did! It's not that you have to use more nutes (stronger dose), you have to use "complete" nutes" (with all the secondary and trace elements. A lot of growers use hydroponic nutes with soil-less mixes.

    And, like Fishheadbob (don't you just love that name?) said, don't overfeed! The two most common mistakes are overfeeding and overwatering.
  16. sillypuddy

    sillypuddy Member

    Well, I've got 20,000 initial lumens from a series of 6500K CFL's for two 3-month-old female sativas. I know this is less than a powerful HID, but those things have to be a couple of feet away from the plants, whereas these are within 3 inches. If anyone wants, I can give progress updates.
    By the way, can anyone tell me if I need to fertilize Pro-Mix soilless medium more often than I would fertilize soil? If so, how much more?

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