I used a string of the "nitelite" size bulbs, which come in 4 watt and 7 watt plus there's other bulb shapes in higher wattages, so you could pick and choose the total wattage by simply adding up the individual bulbs to see how much realative heat the entire string is contributing.

The tiny miniature bulbs may only be a watt apiece, but if there's 50 or 100 on a string, that's about the same as a household bulb but the heat is distributed wherever you place them. I chose them partly because they were what I had on hand and also because there is little danger of overheating. The problem with miniatures is they are wired in series, so if one bulb fails, that entire string goes out.

With the larger nite lite types, they are wired in parallel. If a single bulb dies, the remainder stay lit.

If you have concerns about setting up any of my suggestions, maybe you know an electrician or a friend who has electronics as a hobby and they could offer assistance in getting it set up.

I kinda figure people string these things up on homes and trees every Christmas season, totally outdoors in the weather, so under the control and shelter of a greenhouse environment, it should be safe enough.

Just make sure you shut off or disconnect the power before manipulating the lights, watering, etc. I'm not a nanny-stater, but I want people to be safe and only do what they feel comfortable with.

-Ed

Thanks for the info Ed, I'm sure they are totally safe :). I just recently had a little kitchen fire which freaked me out so now I'm constantly checking everything around the house. Probably a normal reaction. Yes, they are designed to be left on for hours and hours. Probably the worst thing that would happen is you could melt any plastic sheeting left nearby if the bulbs were touching.

Your plants looked great though! Eventually I'll get around to doing some season extending here myself!

Very nice! That's a ton of tomatoes!