Checkerboard zig zag lighting has been done for years. With a custom lighting controller/flip/loadcenter, you can have any number of lights and ballasts on. With 20 lights, 10 per greenhouse, you can control lights, with a PLC, to have all the lights on, or half on, or even 2 on, then 2 more, then 2 more, etc, until all 10 or 20 are on, time delayed. But if you decide to hot flip half the lights in each greenhouse for 6 or 12 times a day, the contacts will arc more and burn out sooner, better to power off ballasts, even for a few seconds, every flip cycle, with a PLC you have do an off/on cycle in 1/100 sec.