What if you used a 3-4" or larger PVC pipe to grow in. cut it to 2-3 feet and stand it vertically. mount the bulb in the pipe at the top. (42 watt CFL?) This could be good for a SOG grow. PVC is white and reflective.
For pots maybe 16 oz cups or some other tall skinny pot
For improvement you could place a fan at the top pulling air out.
For pots maybe 16 oz cups or some other tall skinny pot
For improvement you could place a fan at the top pulling air out.