Gather supplies. These items can be found at any hardware store or home improvement center: inexpensive plastic utility shelving, a shop light for each shelf, ordinary fluorescent tubes, (two per shop light), a light timer and a power strip that can accommodate all the plugs. If the setup area isn't close to an electrical outlet, get an extension cord, as well.
Set up the shelves as near as possible to an electrical outlet and attach the power strip to the middle shelf near the back using twist ties. Putting the power strip in the middle, instead of at the top or bottom, ensures that each shop light cord can reach it.
Plug the light timer into the electrical outlet, with settings for the amount of time all the lights will be on each day.
Assemble the shop lights. There usually isn't much to be done here except to remove them from containers and insert the fluorescent bulbs. Expensive grow lights are not necessary to produce good results. Connect the hanging chains and hooks to the tops of the shop lights.
Suspend one or two shop lights, depending on the shelf width, from the bottom of each shelf so that the lights are set to shine directly on the shelf below. Using the chains and hooks also allows easy movement of the lights, up or down, to provide closer or more distant light. For the top shelf, suspend the light from the ceiling.
Connect all the shop light cords to the power strip attached to the back of the middle shelf. To keep the cords orderly, tie or tape them to the shelves. While connecting the lights, switch the power strip to "off." Turn it on after connecting the power strip to the light timer.
If the indoor greenhouse is set up in a cold or drafty basement or garage during winter months, hang clear plastic sheeting on the outside of each shelf to keep in warmth and moisture. However, if the greenhouse is in a heated basement, garage or other protected area indoors, the plastic sheeting is not necessary.