I closed in a 20'x 8' porch for a greenhouse on the southern side of my house two years ago. It must have been winter, because there was lots of light at the time. Now, I find that the oak trees around the house shade most of the windows, and the wooden porch roof does too. Sooooo, I'm going to get lights in there and attach to the ceiling. Would big florescent lights work? The skinny lights I got with a grow kit hardly put out any width of light at all. They don't even cover one tray of seedlings. But, they can be moved close to the plants. Anyone have a greenhouse lit artificially?

My greenhouses are anything but dark, but I do supplement the light during the fall and winter months with fluorescent lights. I have 4 fixtures x 4 tubes of T-8 x 4' in each GH and they are all on timers. The shorter the day-light, the longer they are on. I use really full-spectrum tubes not the ordinary "soft" light tubes.

You can purchase longer length tube fixtures for larger areas.

Another project to plan for. I'll never get bored. Do you just use the lights for seedlings, where you need it close?

Since these lights are all in greenhouses, I don't really use them close to my plants. My greenhouses have wire shelving and there are 3-4 levels of shelving. The closest plants would probably be 24" and the greenhouse flooring (where I have plants as well) will be at least 5' away from those lights. I do use some LED grow lights over specific "baby" orchids, but that's another universe of lighting that I won't get into here. Those LED's are really expensive compared to the basic broad-spectrum T-8's.

If you are growing in a house-setting, with weaker, indirect natural lighting, you could certainly use those T-8 fixtures as good light sources. I would position my plants within 12" of the fluorescent tubing. The tubing produces very little heat.

When florescent lights are 1 foot away from the plants, they only receive half the amount of light that the lamps emit. For every extra foot away from the plants the lamp is, the loss of light is exponential. The new LEDs are good, but if you want good light from a farther distance, you pretty much should go with metal halides. They also do a good job with heating the greenhouse in the winter. Tom

I stated "within 12" away", using 12" as the maximum distance. Metal halides are great IF you have the space and can tolerate the heat they emit. In my opinion they aren't useful in small settings or small greenhouses, which I have. I think they are best used in commercial environments. Again this is just my opinion and I am perhaps the last person to ask about metal halides since I have never used them. As far as heating greenhouses with them, they certainly could be used for that but those lights would have to be on all night when the weather turns chilly. I don't think most tropical plants, particularly orchids, would do well with 24 hours of light, for weeks, if not months at a time. Perhaps that 24 hrs. of daylight would benefit growing seedlings.

My LED's are within 6" of my "baby" orchids but are on timers so that they shut down around 10:00 PM. All my tropical plants will be in the dark for a minimum of 8 hrs.

Texas didn't say anything about details so I was just trying to cover the bases.