Light and heat

[slippery_biscuit]

I have a question regarding my greenhouse (small, 8 x 12). Winter is coming and the available light is fast decreasing. I have a 400 metal halide lamp installed for a boost along with a heater. Now that it is stuffed with orchids I am wondering if I should concentrate more on temperature control or available light?

Unless redirected here the upcoming plan for temperature will be mid to upper fifties at night and lower seventies in the day. There are a lot of catts and other higher light orchids in the greenhouse, but I am not sure what the winter light requirements are. There will be mostly clouds overhead and the sun that does come out will not be high enough to shine directly onto the greenhouse. The MH lamp will not cover the entire greenhouse, so I'm debating to purchase a second or else one of those motorized tracks so that the light can cover both ends. If the light needs to be addressed. Perhaps the light loving plants under the light and the others at the far end and stay with what is in place?
Winter days start around 7:00 am here and it starts getting dark about 4:00.
thanks, jjs

[Cynthia, Prescott, AZ]

Can you remove your shade cloth during winter, or have you already done that?

[slippery_biscuit]

I only had a shade cloth for a couple of hot weeks back in June or July. The greenhouse location puts it in shade for a couple of hours in the middle of the day. Those two hours have now ben stretched into several hours of shade during the day.

[Cynthia, Prescott, AZ]

You might want to research your plants to put them in the order of high light to low, and put the light fixture at one end with the high light plants placed closest to the light.