Is 21,750 lumens enough?

Enough for 4 plants in a 21x26x30 inch (tall) cab using CFL's only? I'm only topping. No other LST stuff. No scrog. Plants can grow taller. Another 15-20 inches leeway.

I'm going into flower soon and need to know whether I should boost my lumen output. So far I've been plauged by leaf burns throughout veg. I've decided I don't like that and will not have the lights on top of the plants during flower. 3 inches away min.

Right now have 9.5k lm on soft white and the rest on bright white as I finish the last week of vegging. I was thinkiing less lumens might be needed cos it is such a small space.
I know conventional wisdom says 8-10k lumens per plant but in such a small space does this apply?

i think you could smelt iron with that set-up. lumens are human-eye-subjective........ my friend goes 200w equivalent per plant. distance is the key factor. keep'em close.

Your lumen count matters less than how close your lights are, what arrangement they are in, and reflectors used, etc.. Don't place too much emphasis on lumens.

...this is a Really vague question (and it gets asked alot)


in some cases you could get away with 1500 lumens.

why?

cause some people dont smoke that much

so, what is enough for you?


on that note, you dont really want to go over 10k lumens.

there is no real added benefit. (too much heat vs limited returns)

but anyways, there is a great difference between 10k from say 600w hps and 10k from cfls.

..you probably could go 20k lumens per plant with cfls and not have any troubles except heat.

the spectrum is usually highly spiked in the green. and plus the light is diffused, not concentrated. and plus it drops off very very quickly in intensity.

to make a long story short.

if you arent satisfied with your yield you need to add more light.

but if you are going above 250w , you might as well go hps.

less heat to deal with and more light.