For those "Handy Persons", I made a 12x22 box out of 1x8's Covered the top with 12" Aluminum Flashing Inside the bottom I mounted some 1x3's about 6 in in from each end Mounted a light socket in the middle of the 1x 3's, Use 2 / 25 w light bulbs wired to a dimmer switch. I made another 1x4 box to fit on top, also covered with 12" aluminum flashing. Cleated the 2 boxes together. Reason, this helps disperse the heat and reduces hot spots. The flashing also keeps moisture off the light bulbs In the top box I drilled a small hole to install a dial thermometer. In the bottom box I drilled a 1/8th in hole in line with each bulb so I could see if they were still working. A little paint or stain, a modicum of care, your biggest repair expense will be an occasional light bulb My cost was less than $15, but I had the wood Happy Growing Byron