How much do i need?

I have a stealth grow cabinet I am fine tuning. It is 40"x18"x50" and i have two shades i made out of aluminum ducting and both have 3 bulb spots. What wattage and number of bulbs should i use??

Minimum 100 watts per plant
SH420

Oh I may want to add i want to scrog out the small space...

At minimum you want 2,000 lumens per square foot. Assuming you're keeping the lights like 4 inches from the canopy with CFL's. 5000 lumens per square foot is better.

I agree with posts above. I would add 3 bulbs with 300w each one.

You can start with 3 26w 5000k for veg but for flower you should jump to at least 3 42w (actual wattage) 2600k. 3 65w are doable if you don'y have space/heat issues...Keep those lights VERY close during flower.

Thank you for all the help!

The more you can fit and still deal with the heat the better your harvest will be. I did 5-6 grows using all t5ho lighting i packed over 500w in a 18x48x36 closet space and pulled 2 zips per plant 4 plants.

I beam 8 42 watt bulbs from the top and 1 from each side total of 420 watts that's 28,000 lumens over 6 sq. Ft .works just fine for me ,pulling .5 grams per watt on a good grow.for ventilation I use a 100 cfm bath exhaust fan to get the heat out and 2 oscillating fans,1 blowing across the tops ,I aim for the 1" -2" space between top of canopy and bottom of lights.The other fan I blow up from the bottom through canopy.This is what I have to work with ,I got it tight,wish I could go bigger but I can't,but this does the trick.

2x 125w Fluorowings! http://bit.ly/1lUFzDf = 14,000 lumens.

I used 2 105 watt cool light flowering bulbs and 3 24 watt warm light for veg, almost 300watts