Did you look "growing under light" forum?

Right. The Growing Under Lights forum and the Growing from Seed Forums both have very helpful FAQ sections that will answer your questions in detail. There are also lots of discussions there - especially this time of the year - on set-up plans, types of lights, using heating mats, etc.

You'll find them quite informative.

Dave

Growing Under Lights

Growing From Seed

Here is mine. The chains simply attach to the shelf above with cup hooks. It makes them adjustable in 3/4" increments. If some trays have shorter seedlings than others they can be raised using blocks under them.

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I cannot move my lights but it is easy to adjust heights of the trays with blocks, books, boxes, whatever. When I'm growing a variety of things each shelf may have plants at several levels. It works fine.

Heat mats are helpful but often you can find a warm place in your home that works well, also. I set tomatoes and peppers sown in a tray with a plastic cover on a shelf OVER the ballast for the light below. It is pleasantly warm there and speeds germination. I've heard others have warm spots on top of refrigerators and TVs or by hot water heaters or furnaces. If you're germinating alot of warmth loving plants, the heat mat would probably be less trouble and worth the cost. The added warmth increases germination rate and speeds up germination significantly for me.