Agree that you don't need to order special grow bulbs for seedlings. Lots of discussions here about that fact. But if you want to use them for some reason then if they will fit will depend on the bulb. Length isn't the only issue, so is the diameter and the pin distance, and if the ballast in the fixture will be strong enough to trigger them. Some of the chip board ballasts won't. Usually if they are the same diameter of regular shop light bulb then the pins will fit. Dave

Oh boy, I just went though this. You can get smaller lights, but they may not be strong enough. Everyone here suggests 40 watt, and it is nearly impossible to find any under 48" long that are 40 watts. The ones they have at Lowe's & Home Depot are only 20 watts. I asked at Lowe's and they told me that it isn't possible to make a 40 watt bulb that small. I'm not sure that's entirely true, b/c I did see some on the GE website, but everywhere I called locally didn't have them. I even called specialty fish aquarium stores, because that's what this type of bulb is made for. Even they didn't carry any. The two websites I found online that had them had to special order them so it would take several weeks to get them. Plus, they are pretty expensive - the bulb itself plus special shipping since it is breakable. Right now, I have the 24" fixture from Lowe's with 2 20 watt bulbs in it. My seedlings are doing ok, but not the best. You have to keep the lights directly on top of the seedlings (just not touching them), and if the pots stick out from the sides of the light, the seedlings will get leggy. Some others here suggested getting 2 24" fixtures, so you have 4 bulbs, and that can increase your growing space. I haven't tried that yet because I really don't want to spend another $40, so I only have 25 tiny cells under the lights. Hope that helps. Good luck!

You people in southern California obviously aren't paying attention. I have posted several times on this forum where to get fluorescent light fixtures and CFLs cheap but apparently no one is reading the posts. Right now Southern California Edison is subsidizing the costs of fluorescent light fixtures so you can get a 4 foot long single tube fixture that can use either a T12 or T8 tube for the ridiculously low price of $1.99. They are also subsidizing the cost of CFLs so you can buy them for an equally ridiculously low price of only 20 cents each, that's cheaper than an incandescent bulb. I bought two cases of them, so I now have a lifetime supply. Someone on Craigslist is selling used T8 and T12 fluorescent tubes in good condition that they got when the redid the lighting system in a large building for only 50 cents each. You have to look at the total cost of your lighting. Why use an expensive light fixture and bulb when two cheap fixtures and cheap bulbs will cost a fraction of the price and emit more light. Think!

I have replace them in three different houses! Because I hate them... and they are hideous! Like the others have said, they leave suprisingly small holes in the ceiling! I really only had to use touch up paint where I had to patch the ceiling holes, the rest was painted to match already, BONUS! As far as the light "box"(or whatever its really called) already being in place, once yes, two times no. The first time there was just a wire hanging out of the ceiling, I called an electrician who just used toggle bolts to secure the little silver-hanging-bar-bracket-thing directly into the drywall of the ceiling and wired it all together. The next time that happened I did it myself and chose to spend the $150.00 I had paid him on something pretty for me! My most useful tip is just to have help getting the light box itself down from the ceiling, they are crazy heavy and very awkward! Good luck! It's a great and easy project! Here are some pics of one of the ones I did. Before After