Technically it will grow more than just seedlings, however taking from the inspiration of my friend the Cheap Vegetable Gardener and his computerized grow box. Of course, he most important part about any project is to take the first step. So I picked up 6 sheets of 1 1/2” rigid insulation, 2 - 4 foot long florescent light fixtures, some metal duct tape and an outlet timer. Using the metal tape I connected the seems until I had a box. Make sure to place the tape on both sides to prevent the corners from pivoting on the edge. As you complete the corners leave one corner with only the exterior tape as that will be your hinge, I placed mine on top to trap the most heat. I also try to add shims under the back side to allow water to come out when you water your plants. Once you have these steps completed then you will have a tunnel, so you need to close off the sides. As the lamps are just a bit longer than the panel I place the first side on the outside, as if it was a top piece. To hold the lamp I also put a shorter piece inside that provides a ledge for the lamp to rest on. Make sure to tape all the seems on the inside for each piece, not only does it look better but the extra insulation will trap additional heat generated by the florescent lights. On the other side I needed to cut out some of the insulation to create a dad as my lamps were 1/2” too long but one thing you can do is get a sheet of 1” thick insulation and some construction glue and glue the panels to create the channel for the lamps. Finally once all the sides are taped together and you have your box with the lights inserted, leave the lights on for a couple hours with a thermometer inside. Come back and check the temperature. You might need to add vent holes that can be removed during the day and returned during the night. Then just put your plants in there and enjoy your grow box.