i have a sun room on the east side of my house,not a whole lot of natrul light but some.i was going to put a few 4 ft flouro's in there for some extra light.well see how it turns out this winter,i hope it works.it should.18/6, veggies don't require light cycle changes to bear fruit. Tomatoes for example flower from excess sugar. I had a few different kinds I grew in my veg room, everything seemed to do way better with the 6 hours of darkness than with 24/0.