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Lighting spectrum question

Uth33

New Member
I have my plants well into flowering, but I feel the hps light is not quite strong enough for the number of plants. If I were to throw some t5 fluorescents in there to help boost light, would that have a negative affect considering ones more red spectrum and ones more blue? Or is it best to just leave them with the hps?
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
I feel the hps light is not quite strong enough for the number of plants.

Well, it's not the number of plants that determines this, since, to the best of my knowledge, no one has figured out a way to get a light's output to fall only on plants, lol.

What wattage is your light? What size is your space? Does the shape of your grow room match the shape of your light's footprint? Is your reflector air-cooled or open? What kind of strains are you growing? Equatorial landrace sativas evolved in an environment with lots of available light-energy (which is why the leaves look different than indicas). Are your grow space walls highly reflective (Orca film, bright white paint without too much (or any) sheen, mylar installed with no wrinkles/sags/creases, et cetera) or something that isn't nearly as reflective? Et cetera.

If I were to throw some t5 fluorescents in there to help boost light, would that have a negative affect considering ones more red spectrum and ones more blue? Or is it best to just leave them with the hps?

More light is generally a good thing. Yes, spectrum matters. But it's not the only thing that matters. Some people actually plan on mixing things in that regard. Before LED panel grow lights and such, when "big lights" basically meant HIDs, either high pressure sodium or metal halide, the suggestion used to be to use 75% HPS and 25% MH in the flower phase (and many people have done the same thing when growing with CFL bulbs).

Therefore, no, I don't expect that adding some fluorescent bulbs for supplemental lighting will hurt anything.
 

Cultivator

Member of the Month: Jan 2013 - Plant of the Month: Nov 2016, May 2018 - Nug of the Month: Mar 2018 - Creme de la Creme Photos: Oct 2016
So the question is open to say the least. Light is the no1 thing to consider in any grow. Min 400w per m2 preferably more. SO most people make the mistake of running too many plants in a space. i say max 4 plants per 600w hps although with minimum veg time you could run more. Plant number are irrelevant really, it always boils down to how much light per m2 then how ever you fill that space is optional.

T5's are the worst possible supplemental lighting for a flowering plant though. They have very little output and penetration. Just add more hps if thats an option. if not ditch some plants.
 
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