par vs. watts

dundadundun

;sup' dog? ;woof and a wwwoof!
Jan 21, 2009
4,295
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38
S.E. PA
i have been thinking lately when i see suggestions for low light plants and folks "only have 1 wpg". i've almost been wanting to buck the system.

let me explain:

  1. i'm running cfl's
  2. @ ~1.2 wpg
  3. raised ~a foot above the water... ~20" +/- above the substrate
  4. with no co2 or other carbon supplements
  5. with a play sand substrate
  6. no root ferts thus far
  7. and growing rotala sp nanjenshan, submersed riccia fluitans, red root floater, riccardia chamedryfolia, nymphae lotus, etc.

when looking at the plant finder @ plantgeek i find that these particular plants fall under medium to high light requirements.

when people ask about their lights often it's suggested that ~1.5 wpg is bare minimum. in a way i agree... everybody likes healthy looking plants, you know? in a way i'd have to disagree... i'm growing "high light" plants in <1.5 wpg right now.

knowing that 1.5 wpg is suggested as bare minimum (low light), cfl's "have re-strike issues" and these plants are growing fine and healthy for me below that "limit" i have a tendency to want to suggest them to other people also, but refrain.

so, now you see my dilemma... let's talk. what are your thoughts?
 
hmm well if i can grow med-high light plants without highlights and suggested co2 then thats awesome!
let me know how it goes
my petco only sells lowlight things so i cant get anything more "complicated"
 
that's not all that's in the tank. the tank has been going for years. the substrate has been in there for a couple months. surely i could get better growth with a natural substrate capped with sand and/or adding co2 but i'm not seeing the need for a special substrate necessarily. i also have minimal filtration/circulation, an hob and airstones in the tank.

a good place to get plants is right here... in the marketplace. i'll never go to a store again for them... unless it's something i can't find otherwise. fat chance minus a few online retailers.

one side benefit to my tanks is low maintenance. i still do water changes, clean filters, etc., etc., but i don't trim plants every week. some of them even color up for me.
 
I think primarily it is just an issue with the descriptions provided on APC. I'm surprised they list those plants as requiring medium to high light....I've grown all of those in very low light without issue.

Riccia will just about grow in the dark, so if you've got it submerged with even a little light, it'll be fine.

So less of a "let's redefine the wpg 'rule' " and more of a "let's clarify plant descriptions" discussion.

For most of your more colorful stems, they would not grow well in your setup.
 
you know, i think it might be a little of both, but yeah more of a better plant description...

i would like to try some more red plants to see how they do honestly. i was surprised that rotala rotundifolia colors up at the tips for me (location dependent of course).

EDIT: maybe a better title would be "low light? really?".
 
Think of it this way. Watts are a measure of the quantity of light. PAR is a measure of the quality of light. If you had 10 wpg of metal halide, but none of the light was in the two narrow bands of wavelength that plants actually use for photosythesis your plants would grow better under your current lighting.
 
i would refine that description further, subrosa. i'd say more along the lines that watts are a quantity of power and par is a quantity of usable (quality) light. watts actually has no direct relation to light output except when comparing identical light sources or when wattages being compared or not even in the same ballpark. for instance 30 watts of any fluoro will never be 500 watts of mh no matter what you do to tweak it or how it's tested.
 
Here is the low down in my book...
The WPG rule only applies to T8 or T12 fixtures as that is what the rule was made for. T5, CFL, and PC fixtures do not apply to this rule as they give our more/less light per watt then a T8 or T12 fixture.

I am not a "plant" expert, but the reason you are getting good growth from those plants with "1.5WPG" or "low-light" is because it gives out a good deal more light then a T12 fixture.
Regards,
Jake
 
not to mention, and I have made the mistake and still do, people focus on it too much. Probably should be labeled something along the line, how do you want your plants to grow? I personally want and aim for high tech. I love watching my plants grow crazy fast. But then as mentioned above, I pay the price by always having to trim. I also believe that some plants grow a more natural and beautiful look with what best suits them. My anubias, thrive in my "low light" non co2 tank every week new leaves, When they were in my "high light" co2 set up hardly any new leaves. Why? well as stated to me, in the high light other plants out competed the anubias for nutrients. Now that they are in their own tank with nothing to compete with they thrive. Will certain plants require the "high light tank" yes but IMO plants will grow the way you want them too, just a matter of what you provide them.
 
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