I've got a 20 Long and a 20 Tall, both with one 18" 15W 10,000K florescent light.
Are there any live plants I can keep with that amount of light? If so, are there any that require little to no extra maintenance (i.e. CO2, ferts, etc.)?
For the 20 tall, you could get a 10 gallon hood that's made for incandescents and put 2 CFLs in it and grow pretty much whatever you want.* Otherwise, what they said. you probably wouldn't need any ferts or co2 with that light.
*Might need ferts, possibly co2 although you could probably dose Excel instead. If you just used Flourish and Excel that's not much maintenance.
You shouldn't need either. Just make sure with the Java Fern that you don't plant the rhizome, only the actual roots. It's usually better attached to something like dritfwood than planted in the substrate.
Flourish- or something cheaper like leaf zone might help a little for trace nutrients- but at that light level they won't grow fast so will most likely get everything they need from the water without ferts.
I also grew star grass, water wisteria, and bacopa (2 varieties) at that light level with no problems before I upgraded- I did use trace element ferts- I probably didn't need to though.
I'm going to get some wood from the LFS for my new tank (love the natural look versus the ceramic decorations) and get some java moss and java fern for the tank!
I got both wendtii and walkeri crpyts and they seem to grown rather nicely. Now the issue is i cant figure out which ones are growing like beasts haha. They like low light and once they start growing they really turn out nicely.
Good luck... You should be able to find Java Fern in your LFS- for Java Moss you may need to check online... I highly recommend the classified section here on AC.
I've had more success with online plants than LFS plants.