is 20,000 lumens of flouresent lighting enough to grow a decent crop..
i have the lights in a 4ft y 4f closet..

thanks in advance..

No need to worry about lumens, if your going to focus on anything like that focus on PAR. Just get the proper kelvin for the stage of growth, if you can find the nanometer rating, thats even better. And as much wattage as you can afford. You will need more wattage in the red than you will the blue.

The below graph is how we see light and how the lumen rating is derived. What may be very dim to you, could be very bright to a plant and vice versa.


This graph shows how plants see light. Now if you are using lumens as a guide look how much range you are missing.


The article where these graphs came from can be found here:
Light and Plants

I do not endorse this company, they just have a very informative article.

i am a newb so this stuff confusing.... do u think that i can get a decent crop with this lumen output.. planning to plant 10 seeds..

I doubt it.