"Word is that is not the best for the plants."

Unless you are growing something like poinsettias, don't worry about it.

Most people would just turn on a regular light bulb. Besides, green light is not neutral.

the sun has a very full spectrum, and it's the best thing there is for plants.

edit: sorry, I did not gather that photo-period was the concern, but sounds like maybe it is. if so, my comment makes no sense sorry.

I agree - unless you are growing specific photoperiodic plants, just use a normal lamp for when you are working in the room.

If you are growing photoperiodic plants, then an opaque grow tent with added ventilation is the solution.

During the dark cycle for 90% of plants it is fine to interrupt their cycle without having any faults. Standard incandescent bulbs would suffice and not reduce flowering or production.

Example, i live inner city. I have a pretty large outdoor garden almost every year that spills out into my alley and in front of my house. The 400w hps street lights are directly over my property front and back and constant traffic headlights throught the night light up my garden. I never have any issues with blossom drop or any other deformity that light interruption might cause.