light cycle for proper flowering.
 

Ron or anyone, Some plants require a flowering light cycle for proper flowering. My tomatoes have started producing flower clusters under 18 hours on 6 off. Will they produce more clusters of flowers if I switch the light to 12on 12off. Do tomatoes require a flowering cycle for good production. If so how long do I run the flowering light cycle. Should I switch back to 18on 6off after that.

Tomatoes are indeterminate which means they are not affected by the number of hours of light or dark periods. As long as the right environment is provided they will produce fruit year round. For totally indoor growing under HID's then 18 hours is fine to compensate for less light.