is it a good idea to paint cement white

[shiloh]

got a room and painted the wall flat white..is it a good idea to paint the the floor (cement) flat white?

[Dutch Pimp]

got a room and painted the wall flat white..is it a good idea to paint the the floor (cement) flat white?
probably not necessary...I did that once...made the floor slick as snot on a marble...:D

I just lay foil on the bottom for some reflection

[Rusty Trichome]

Thinking long-term:
Unless using an epoxy or enamel paint specifically for concrete, you'll eventually be tracking-in little specks of flaked-off paint. Chemical resistance would also be a plus. (stains and adhesion degradation) I was a foreman for a concrete refinishing company that included sealers and coatings for industrial and commercial floors, aircraft hangers, loading docks...

Also, you can never really un-paint concrete unless you have a shot blaster, sand blaster, diamond grinder, or a Tennant Eco-prep machine. (a ride-on belt sander)

If using HID's likely would be a small, rather undetectable measure of help, but if using anything less for lighting...it would be a waste. Effective range of CFL's wouldn't extend to the ground and then be reflected back to the plant.