Best Light Cycle For Growing Tomatoes

i have on a flexable 18/6 but the place there in is swagy cause my mj plants in the nice room are on 12/12 and i was woundering if i could put them in there

I had my tomatoes and peppers in my 18-6 until I got my flower room set up. They did ok but It seemed like too much light.
Now they are in the 12-12 and are doing great...It is only a 400 watt SV but I have the toms and peppers on the floor, herb on a bench. I want to try some other stuff.