im growing under similar lights. i actually mad a plywood board with cheap wiring and 6 sockets.

ive got 3 23-watt daylights, 2 60watt floodlights (incandesent) and a 60watt household reg. bulb since one cfl died.

theyre finicky, expect to replace one by the end of the month. besides that, my plants love em, arch towards the cfls and not the floods yellowish light.

(ps: my plants are happily 2 ft tall at 7 weeks old and 2 weeks flowering)

PPS: by grow medium, he meant soil, rockwool, etc, not crop size. looks like soil tho