You would need at least 5 of those in order to hit 50 w/SqFt formula target.

4.5' x 1.5' = 6.75 Sq Ft of grow space
6.75 x 50 = 337.5 Watts of light
337.5 / 65 = 5.2 LOA fixtures needed

For the same money you could get better fluorescents. For example, www.100bulbs.com, has several large CFLs that have the ballast built-in for a comperable light, eg. 105W-$25.
pastor420 Reviewed by pastor420 on . Planning on using this light, LOA Fluorexâ?¢ Flood Light Model No. 9266 Watts Used 65 Incandesc attage Equivalent 500 Size (H x D) 4.25 x 3.5 Lumens 4550 Efficiency 87% Life 10,000 CRI 82 Color Temp 6,500 Op. Voltage 120V Rating: 5